Nucleoside analogs

ABSTRACT

Provided are compounds of the following formulae: A phosphonomethoxymethyoxymethyl purine/pyrimidine derivative of the formula ##STR1## wherein X and X&#39; are the same or different and are hydrogen or alkyl. R and R&#39; are the same or different and are hydrogen, alkyl, hydroxyalkyl or alkanoyl and 
     B is a purine or pyrimidine base. 
     A compound of formula (VI) ##STR2## wherein X is halogen, Y is S-phenyl, Se-phenyl or halogen and B is hypoxanthine, xanthine, guanine, 8-bromoguanine, 8-chloroguanine, 8-methylguanine, 8-thioguanine, 3-deazaguanine, purine, 2-aminopurine, 2,6-diaminopurine, adenine, 3-deazaadenine, 8-aminoguanine, 8-hydrazinoguanine, 8-hydroxyguanine, cytosine, 5-ethylcytosine, 5-methylcytosine, thymine, uracil, 5-chlorouracil, 5-bromouracil, 5-ethyluracil, 5-iodouracil, 5-propyluracil or 5-vinyluracil, 2-acetamido-6-diphenylcarbamoylpurine, 6-N-dimethylamino-methyladenine or 6-N-pivaloyladenine. 
     A compound of formula (VII) ##STR3## wherein B is guanine, 8-guanine, 8-bromoguanine, 8-chloroguanine, 8-methylguanine, 8-thioguanine, 3-deazaguanine, 8-aminoguanine, 8-hydrazinoguanine, 8-hydroxyguanine, cytosine, 5-ethylcytosine, or 5-methylcytosine.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional of application Ser. No. 08/391,312 filed on Feb.17, 1995 which is a continuation of U.S. Ser. No. 07/765,774, filed Sep.26, 1991, now abandoned, which is a continuation-in-part of U.S. Ser.No. 07/481,569, filed Feb. 22, 1990, now abandoned, which is acontinuation-in-part of U.S. Ser. No. 07/352,303, filed May 15, 1989,now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns nucleotide analogs and their compositionsand use. In particular, the invention concerns antiviral (includingantiretroviral) and antitumor phosphonomethoxy-methyloxymethylpurine/pyrimidine derivatives and4'-phosphonomethyl-oxymethoxytetrahydrofuranyl-1'-purine/pyrimidinederivatives.

2. Background Information

Infectious viral diseases are recognized as an important medicalproblem. Progress against infectious viral disease requires thedevelopment of drugs with selective antiviral activity while remainingbenign to normal cell lines. A number of antiviral agents currentlyunder study which seem to possess some selectivity are nucleosideanalogs. In general, these compounds are structural analogs of thenaturally occurring nucleosides. Structural modification in either thepurine or pyrimidine base nucleus and/or the saccharide componentresults in a synthetically modified nucleoside derivative which, whenincorporated into a viral nucleic acid forming process, acts to disruptfurther synthesis of viral nucleic acid. Effectiveness of theseantiviral agents depends on selective conversion by viral enzymes, butnot by host enzymes, to the corresponding nucleotide analog which isthen converted to the triphosphate and incorporation into viral nucleicacid occurs. A problem with this antiviral strategy has been theemergence of certain viral strains whose enzymes poorly promotephosphorylation of the nucleoside analogs. To circumvent this problem,intact nucleotide analogs appear to be potentially quite useful asantivirals for incorporation into viral nucleic acid.

Reist and Strum in PCT/US 84/00737, published Dec. 6, 1984, disclosednew phosphonic acid analogs of nucleoside phosphates which are useful asantivirals for incorporation into viral DNA. The structural formula forthese compounds is shown below as 1': ##STR4##

In the Reist and Sturm compounds, B is a purine or pyrimidine base: R₁and R₂ together complete a β-pentofuranose sugar or R₁ is H and R₂ is Hor hydroxmethyl; R₃ is H or OH: X is H, OH or together with Y iscarbonyl oxygen and Y can also be H; Z₁ and Z₂ are H or alkyl.

Similarly, the synthesis and anti-Herpes-Virus activity of phosphate andphosphonate derivatives of 9- (1,3-dihydroxy-2-propoxy)methyl!guanine(Formula 2' were disclosed by Prisbe, et al., in J. Med. Chem., 1986,29, 671. ##STR5##

Other phosphonate nucleotide analogs of the Formula 2' type whereinX=CH₂ have been described by R. M. Riggs et al., Nucleosides andNucleotides, 8(5&6), 1119-1120 (1989); D. H. R. Bouton, et al.,Tetrahedron Letters, 30, No. 37, 4969-4972 (1972); and H. Tanaka, etal., Tetrahedron Letters, 30, 2567-2570 (1989).

Adenine phosphonic analogs (Formula 3') and their syntheses aredisclosed in the UK Patent Application of Holy, et al., GB 2,134,907Apublished Aug. 22, 1984. ##STR6##

In formula 3', R₂ and R₃ are H or together complete a ribonucleosidering; and both R₄ are alternately a hydrogen and --CH₂ P(O)(OH)₂ group.

A preferred example of one of these compounds, known as (S)-HPMPA(Formula 4') was disclosed by DeClercq, et al., in Nature, 1986, 323,pp. 464-467 and earlier by Holy, et al., Nucleic Acids Research,Symposium Series No. 14, 1984, pp. 277-278. Phosphonate compounds whichare HPMPA analogs are described in South African Patent 1987/8607. Inapplicant's hands, (S)-HPMPA is only slightly active in mice inoculatedwith Herpes simplex virus-2. In a 21 day protocol 30% of a group ofanimals treated i.p. with 50 mg/kg/day of (S)-HPMPA survived. ##STR7##

There is no teaching contained in these references, or a combinationthereof, which would make obvious the compounds, compositions, and usesinvolved in the present invention.

SUMMARY OF THE INVENTION

Phosphonomethoxymethoxymethyl purine and pyrimidine derivatives,4'-phosphonomethoxytetrahydro-2-furyl-9-purine and 1-pyrimidinederivatives, phosphonomethoxymethoxymethyl-9-purine and 1-pyrimidinederivatives having a cyclic phosphonate group and4'-phosphonomethoxytetrahydro-2-furyl-9-purine and 1-pyrimidinederivatives having a cyclic phosphonate group have been synthesized andfound to possess useful antiviral and antitumor activity.

The present invention concerns a phosphonomethoxy-methoxymethylpurine/pyrimidine derivative of the formula: ##STR8## wherein X and X'are the same or different and are hydrogen or alkyl having 1 to 6 carbonatoms,

R and R' are the same or different and are hydrogen, alkyl having 1 to 6carbon atoms, hydroxyalkyl with 1 to 6 carbon atoms, alkanoyl having 2to 7 carbon atoms, and B is a 9-substituted purine or 1-substitutedpyrimidine base selected from the group consisting of xanthine,substituted xanthine, for example, hypoxanthine, guanine, substitutedguanine, for example, 8-bromoguanine, 8-chloroguanine, 8-aminoguanine,8-hydrazinoguanine, 8-hydroxyguanine, 8-methylguanine, 8-thioguanine and3-deazaguanine, purine, substituted purine, for example, 2-aminopurine,2,6-diaminopurine, cytosine, substituted cytosine, for example,5-ethylcytosine and 5-methylcytosine, thymine, uracil, 5-substituteduracil, for example, 5-chlorouracil, 5-bromouracil, 5-ethyluracil,5-iodouracil, 5-propyluracil and 5-vinyluracil, adenine and substitutedadenine, for example, 3-deazaadenine, and pharmaceutically acceptablesalts thereof.

The present invention also concerns a 4'-phosphonomethoxytetrahydro (or-dihydro-)-fur-2-yl-purine or pyrimidine derivative of the formula:##STR9## wherein X and X' are the same or different and are hydrogen oralkyl having 1 to 6 carbon atoms, the broken line represents an optionalbond,

Y and Z are the same or different and are unsubstituted or halogen,hydroxy, amino- or azido substituted alkyl with 1 to 6 carbon atoms ortogether they constitute an oxygen atom or methylene group in whichevent the broken line is absent, and

B is a 9-substituted purine or a 1-substituted pyrimidine base selectedfrom the group consisting of xanthine, substituted xanthine, forexample, hypoxanthanine, guanine, substituted guanine, for example,8-bromoguanine, 8-chloroguanine, 8-methylguanine and 8-thioguanine and3-deazaguanine, purine, substituted purine, for example, 2-aminopurine,2,6-diaminopurine, cytosine, substituted cytosine, for example,5-ethylcytosine and 5-methylcytosine, thymine, uracil, 5-substituteduracil, for example, 5-chlorouracil, 5-bromouracil, 5-ethyluracil,5-iodouracil, 5-propyluracil and 5-vinyluracil, adenine and substitutedadenine, for example, 3-deazaadenine, and pharmaceutically acceptablesalts thereof.

The invention also concerns a4'-phosphonomethoxytetrahydrofur-2-yl-purine or pyrimidine derivativehaving a cyclic phosphonate group of the formula: ##STR10## wherein X ishydrogen or alkyl with 1 to 6 carbon to atoms, Rb is H or OH

and B is a 9-substituted purine or a 1-substituted pyrimidine baseselected from the group consisting of xanthine, substituted xanthine,for example, hypoxanthine, guanine, substituted guanine, for example,8-bromoguanine, 8-chloroguanine, 8-aminoguanine, 8-hydrazinoguanine,8-hydroxyguanine, 8-methylguanine, 8-thioguanine and 3-deazaguanine,purine, substituted purine, for example, 2-aminopurine,2,6-diaminopurine, cytosine, substituted cytosine, for example,5-ethylcytosine and 5-methylcytosine, thymine, uracil, 5-substituteduracil, for example, 5-chlorouracil, 5-bromouracil, 5-ethyluracil,5-iodouracil, 5-propyluracil and 5-vinyluracil, adenine and substitutedadenine, for example, 3-deazaadenine, and pharmaceutically acceptablesalts thereof.

The invention is further directed to aphosphonomethoxymethoxymethyl-9-substituted purine or 1-substitutedpyrimidine derivatives having a cyclic phosphonate group of the formula:##STR11## wherein X is hydrogen, alkyl with 1 to 6 carbon atoms, R ishydrogen, alkyl with 1 to 6 carbon atoms or alkanoyl having 2 to 7carbon atoms, and B is a purine or pyrimidine base selected from thegroup consisting of xanthine, substituted xanthine, for example,hypoxanthine, guanine, substituted guanine, for example, 8-bromoguanine,8-chloroguanine, 8-aminoguanine, 8-hydrazinoguanine, 8-hydroxyguanine,8-methylguanine, 8-thioguanine and 3-deazaguanine, purine, substitutedpurine, for example, 2-aminopurine, 2,6-diaminopurine, cytosine,substituted cytosine, for example, 5-ethylcytosine and 5-methylcytosine,thymine, uracil, 5-substituted uracil, for example, 5-chlorouracil,5-bromouracil, 5-ethyluracil, 5-iodouracil, 5-propyluracil and5-vinyluracil, adenine and substituted adenine, for example,3-deazaadenine, and pharmaceutically acceptable salts thereof.

The present invention also concerns the following intermediates:##STR12## wherein B is a 9-substituted purine or a 1-substitutedpyrimidine base selected from the group consisting of xanthine,substituted xanthine, for example, hypoxanthine, guanine, substitutedguanine, for example, 8-bromoguanine, 8-chloroguanine, 8-aminoguanine,8-hydrazinoguanine, 8-hydroxyguanine, 8-methylguanine, 8-thioguanine and3-deazaguanine, purine, substituted purine, for example, 2-aminopurine,2,6-diaminopurine, cytosine, substituted cytosine, for example,5-ethylcytosine and 5-methylcytosine, thymine, uracil, 5-substituteduracil, for example, 5-chlorouracil, 5-bromouracil, 5-ethyluracil,5-iodouracil, 5-propyluracil and 5-vinyluracil, adenine and substitutedadenine, for example, 3-deazaadenine; ##STR13## wherein X is a halogen,for example, chlorine, bromine, iodine or fluorine,

Y is phenylthio, phenylseleno or a halogen atom, for example, chlorine,bromine, iodine or fluorine, and B is a 9-substituted purine or1-substituted pyrimidine base selected from the group consisting ofxanthine, substituted xanthine, for example, hypoxanthine, guanine,substituted guanine, for example, 8-bromoguanine, 8-chloroguanine,8-aminoguanine, 8-hydrazinoguanine, 8-hydroxyguanine, 8-methylguanine,8-thioguanine and 3-deazaguanine, purine, substituted purine, forexample, 3-aminopurine, 2,6-diaminopurine, cytosine, substitutedcytosine, for example, 5-ethylcytosine and 5-methylcytosine, thymine,uracil, 5-substituted uracil, for example, 5-chlorouracil,5-bromouracil, 5-ethyluracil, 5-iodouracil, 5-propyluracil and5-vinyluracil, adenine and substituted adenine, for example,3-deazaadenine; ##STR14## wherein B is guanine, substituted guanine, forexample, 8-bromoguanine, 8-chloroguanine, 8-aminoguanine,8-hydrazinoguanine, 8-hydroxyguanine, 8-methylguanine, 8-thioguanine and3-deazaguanine, cystosine or substituted cytosine, for example,5-ethylcytosine and 5-methylcytosine; adenine and substituted adenineand, ##STR15## wherein Y is a halogen, for example chlorine, fluorine,bromine or iodine, phenylthio, or phenylseleno, R is hydrogen or alkylwith 1 to 6 carbon atoms and B is a purine or pyrimidine base selectedfrom the group consisting of xanthine, substituted xanthine, forexample, hypoxanthine, guanine, substituted guanine, for example,8-bromoguanine, 8-chloroguanine, 8-aminoguanine, 8-hydrazinoguanine,8-hydroxyguanine, 8-methylguanine, 8-thioguanine and 3-deazaguanine,purine, substituted purine, for example, 2-aminopurine,2,6-diaminopurine, cytosine, substituted cytosine, for example,5-ethylcytosine and 5-methylcytosine, thymine, uracil, 5-substituteduracil, for example, 5-chlorouracil, 5-bromouracil, 5-ethyluracil,5-iodouracil, 5-propyluracil and 5-vinyluracil, adenine and substitutedadenine, for example, 3-deazaadenine.

The present invention further relates to the following processes:##STR16## wherein R is an alkyl having 1 to 6 carbon atoms or anunsubstituted aryl or an aryl substituted by a substituent such as ahalogen, e.g., bromine or chlorine, nitro, alkyl having 1 to 6 carbonatoms or an alkoxy having 1 to 6 carbon atoms, B is a silylated purineor pyrimidine base, and R is hydrogen or alkyl with 1 to 6 carbon atoms;preferably the molar ratio of compound (IX) to B is 1:1; ##STR17##wherein Ra is an alkyl having 1 to 6 carbon atoms and B is a purine orpyrimidine base; preferably compound (X) is 5 to 10 times in excess ofcompounds (XI) and the preferred molar ratio of compound (XII) to B is1:1; ##STR18## wherein compound (XIII) is preferably in a 5 to 10 timesexcess of compound (V); ##STR19## wherein X--Y is a halogen, e.g., Br₂,Cl₂, phenyl-Se--Z, phenyl-S--Z (wherein Z=halogen) and B is a purine orpyrimidine base; preferably the molar ratio of compound (VII) to X--Y is1:1; ##STR20## wherein R is hydrogen or alkyl with 1 to 6 carbon atoms;preferably compound (XIV) is 5 to 10 times in excess of compound (VII).

DETAILED DESCRIPTION OF THE INVENTION

The compounds of the present invention can exist as optical isomers.Both the racemic and diasteromeric mixtures of these isomers which mayexist for certain compounds, as well as the individual optical isomers,are all within the scope of the present invention. While the racemicmixtures can be separated into their individual isomers throughwell-known techniques such as, for example, the separation ofdiastereomeric salts formed with optically active adjuncts, e.g., acidsor bases followed by conversion back to the optically active substrates,in most instances, for the compounds of the present invention, thepreferred optical isomer can be synthesized by means of stereospecificreactions, beginning with the appropriate stereoisomer of the desiredstarting material.

As indicated above, the present invention also pertains topharmaceutically acceptable non-toxic salts of these compounds,containing, for example, Na⁺, Li⁺, K⁺, Ca⁺⁺ and Mg⁺⁺. Such salts mayinclude those derived by combination of appropriate cations such asalkali and alkaline earth metal ions or ammonium and quaternary aminoions with the acid anion moiety of the phosphonic acid group. Metalsalts can be prepared by reacting the metal hydroxide with a compound ofthis invention. Examples of metal salts which can be prepared in thisway are salts containing Li⁺, Na⁺, K⁺. A less soluble metal salt can beprecipitated from the solution of a more soluble salt by addition of thesuitable metal compound. In addition, salts may be formed from acidaddition of certain organic and inorganic acids, e.g., HCl, HBr, H₂ SO₄or organic sulfonic acids, with basic centers of the purine,specifically guanine, or pyrimidine base. Finally, it is to beunderstood that compounds of the present invention in their unionized,as well as zwitterionic form, and/or in the form, of solvates are alsoconsidered part of the present invention.

Compounds of the present invention also exist in subclasses, with twobroad subclasses being those wherein B is either a purine or apyrimidine base. Of these broad subclasses there are preferred classeswherein the purine base is a guanine or a substituted guanine moiety andwhere the pyrimidine bases are either thymine or cytosine. The mostpreferred class of compounds are those wherein B is guanine orsubstituted guanine.

Compounds of the present invention may also be subclassed according tothe structure of the phosphonate moiety. These classes are comprised ofthe diester, the monoester, and the diacid. Preferred subclasses of thephosphonate moiety are the monoester and the diacid.

The compounds of this invention, including the physiologicallyacceptable salts thereof, have desirable antiviral and antitumoractivity. They exhibit activity against viruses, for example, HerpesSimplex virus I ("HSV-1"), Herpes Simplex virus II ("HSV-2"),cytomegalo-virus ("CMV"), Varicella Zoster virus ("VZV"), influenzavirus, vaccinia, polio, rubella, small pox, cowpox, Epstein-Barr virus("EBV"), measles virus, human respiratory virus, hepatitis virus e.g.,Hepatitis B, papillomavirus and sinbis virus, just to mention a few. Thecompounds also are active against retroviruses, for example, humanimmunodeficiency virus ("HIV"). The inventive compounds also have anantitumor effect. They are active against murine leukemia P388 and otherexperimental tumors.

As mentioned above, the compounds of the present invention are usefulactive ingredients in human and veterinary medicine for the treatmentand prophylaxis of diseases caused by retroviruses. Examples of fieldsof indication in human medicine regarding retroviruses are as follows:

(1) the treatment or prophylaxis of human retrovirus infections;

(2) the treatment or prophylaxis of diseases caused by HIV (virus ofhuman immune deficiency; previously called HTLV III/LAV or AIDS) and thestages associated therewith such as "ARC" (AIDS related complex) and"LAS" (lymph adenopathy syndrome) and the immune weakness andencephalopathy caused by this retrovirus;

(3) the treatment or prophylaxis of HTLV I infection or HTLV IIinfection;

(4) the treatment or prophylaxis of the AIDS carrier state (AIDStransmitter state); and

(5) the treatment or prophylaxis of diseases caused by hepatitis Bvirus.

Examples of indications in veterinary medicine are as follows:

(1) Maedivisna (in sheep and goats),

(2) progressive pneumonia virus (PPV) (in sheep and goats),

(3) caprine arthritis encephalitis virus (in sheep and goats),

(4) Zwoegerziekte virus (in sheep),

(5) infectious virus of anemia (of the horse), and

(6) infections caused by cat leukemia virus.

For use against viral infections and against tumors, the compounds ofthis invention can be formulated into pharmaceutical preparations. Suchpreparations are composed of one or more of the inventive compounds inassociation with a pharmaceutically acceptable carrier. The referenceRemington's Pharmaceutical Sciences, 17th Edition by A. R. Gennaro (MackPublishing Company, 1985) discloses typical carriers and methods ofpreparation.

For antiviral purposes, the compounds may be administered topically orsystemically to warm blooded animals, e.g., humans. For antitumor use,systemic, and preferably, parenteral administration is employed. Bysystemic administration is intended, oral, rectal, and parenteral (i.e.,intramuscular, intravenous, subcutaneous and nasal) routes. Generally,it will be found that when a compound of the present invention isadministered orally, a larger quantity of the reactive agent is requiredto produce the same effect as the smaller quantity given parenterally.In accordance with good clinical practice, it is preferred to administerthe instant compounds at a concentration level that will produceeffective antiviral or antitumor effect without causing any harmful oruntoward side effects.

Therapeutically and prophylactically the instant compounds are given aspharmaceutical compositions comprised of an effective antiviral orantitumor amount of a compound according to the invention or apharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable carrier, as stated hereinabove. Pharmaceutical compositionsfor effecting such treatment will contain a major or minor amount, e.g.,from 95 to 0.5% of at least one compound of the present invention incombination with a pharmaceutical carrier, the carrier comprising one ormore solid, semi-solid, or liquid diluents, fillers and formulationadjuvants which are non-toxic, inert and pharmaceutically acceptable.Such pharmaceutical compositions are preferably in dosage unit form;i.e., physically discrete units containing a predetermined amount of thedrug corresponding to a fraction or multiple of the dose which iscalculated to produce the desired therapeutic response. Othertherapeutic agents can also be present. Pharmaceutical compositionsproviding from about 1 to 50 mg of the active ingredient per unit doseare preferred and are conventionally prepared as tablets, lozenges,capsules, powders, aqueous or oily suspensions, syrups, elixirs, andaqueous solutions. Preferred oral compositions are in the form oftablets or capsules and may contain conventional excipients such asbinding agents, (e.g., syrup, acacia, gelatin, sorbitol, tragacanth orpolyvinylpyrrolidone), fillers (e.g., lactose, sugar, corn starch,calcium phosphate, sorbitol, or glycine), lubricants (e.g., magnesiumstearate, talc, polyethylene glycol or silica), disintegrants (e.g.,starch) and wetting agents (e.g., sodium lauryl sulfate). Solutions orsuspensions of an inventive compound with conventional pharmaceuticalvehicles are employed for parenteral compositions, such as an aqueoussolution for intravenous injection or an oily suspension forintramuscular injection. Such compositions having the desired clarity,stability and adaptability for parenteral use are obtained by dissolvingfrom 0.1% to 10% by weight of an active inventive compound in water or avehicle comprising a polyhydric aliphatic alcohol such as glycerine,propylene glycol, and polyethylene glycol or mixtures thereof. Thepolyethylene glycols comprise a mixture of non-volatile, usually liquid,polyethylene glycols which are soluble in both water and organic liquidsand have molecular weights from about 200 to 1500.

Considering the biological activities possessed by the compounds of theinstant invention, it can be seen that these compounds have antitumorand antiviral properties, particularly suited to their use in combatingviral infections or tumors. Thus, another aspect of the instantinvention concerns a process for treating viral (including retroviral)infections or tumors in a mammal in need of such treatment whichcomprises systemic or topical administration to such mammal of aneffective dose of an inventive compound or a pharmaceutically acceptablesalt thereof. On the basis of testing, an effective dose could beexpected to be from about 0.01 to about 30 mg/kg body weight with about1 to about 20 mg/kg body weight a preferred dosage range. It isenvisioned that for clinical antiviral application compounds of theinstant invention will be administered in the same manner as for thereference drug acyclovir. For clinical applications, however, the dosageand dosage regimen, in each case, must be carefully adjusted, utilizingsound professional judgment and consideration of the age, weight andcondition of the recipient, the route of administration and the natureand gravity of the illness. Generally a daily oral dose will comprisefrom about 150 to about 750 mg, preferably 250-500 mg of an inventivecompound administered from one to three times a day. In some instances,a sufficient therapeutic effect can be obtained at lower doses, while inothers, larger doses will be required.

In the reaction (process) (R1) described above, non-limiting examples ofLewis acids include BF₃.etherate, TiCl₄ and BCl₃.

In the reactions (processes) (R3) and (R5) described above, non-limitingexamples of peracids include the following: m-chloroperbenzoic acid,trifluoroperacetic acid and perbenzoic acid.

The reactions (processes) (R1) to (R5) described above are preferablyconducted at atmospheric pressure and preferably conducted in thepresence of a solvent, e.g., CH₃ CN, CH₂ Cl₂, ClCH₂ CH₂ Cl, CHCl₃, THF,dioxane, diethylether, benzene or toluene.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

The compounds which constitute this invention and their methods ofpreparation will appear more fully from a consideration of the followingexamples which are given for the purpose of illustration only and arenot to be construed as limiting the invention in sphere or scope. Inaddition to the compounds described in the following examples, furthercompounds encompassed by the present invention are as follows:

9- (2-Hydroxy-1-phosphonomethoxyethoxy)methyl!adenine disodium salt:##STR21## 9- (2-Hydroxy-1-phosphonomethoxyethoxy)methyl!cytosinedisodium salt: ##STR22## 9-(2-Hydroxy-1-phosphonomethoxyethoxymethyl!thymine disodium salt:##STR23##

In the following examples, all temperatures are understood to be indegrees C. when not specified. The nuclear magnetic resonance (NMR)spectral characteristics refer to chemical shifts (δ) expressed in partsper million (ppm) versus tetramethylsilane (TMS) as a referencestandard, unless stated otherwise. The relative area reported for thevarious shifts in the proton NMR spectral data corresponds to the numberof hydrogen atoms of a particular functional type in the molecule. Thenature of the shifts as to multiplicity is reported as broad singlet(bs), singlet (s), multiplet (m), doublet (d), doublet of doublets (dd),triplet (t) or quartet (q).

Abbreviations employed are:

ACV (acyclovir)

BID (twice a day)

CDCl₃ (deuterochloroform)

DMF (dimethylformamide)

DMSO-d₆ (perdeuterodimethylsulfoxide)

EMEM (Earle's Minimum Essential medium)

Et (ethyl)

HIV (human immune deficiency)

HSV (Herpes simplex virus)

MuLV (murine leukemia virus)

NOE (Nuclear Overhauser Effect)

PFU (plaque forming units)

φ (phenyl)

TMS (trimethylsilyl)

Me (methyl)

Ac (acetyl)

Pv (pivaloyl)

Ph (phenyl)

All compounds gave satisfactory elemental analyses.

THE INVENTION WILL NOW BE DESCRIBED WITH REFERENCE TO THE FOLLOWINGNON-LIMITING EXAMPLES. EXAMPLES Example 1 Bisbenzoyloxymethyl ether (1)##STR24##

To a suspension of sodium benzoate (5.0 g, 34.7 mmol) in DMF (70 mL) wasadded bischloromethyl ether (20 g, 17.3 mmol) and the mixture was heatedat 70° C. for 16 hr. The insoluble material was removed by filtration.The filtrate was concentrated in vacuo to give a white crystal which wasrecrystallized from ether-pentane: yield 4.5 g (91%); m.p. 39° C.

Analysis: Calcd. for C₁₆ H₁₄ O₅ : C, 67.12; H, 4.92. Found: C, 66.87; H,4.94.

¹ H-NMR (200 MHz, CDCl₃): δ 5.66 (s, 4H), 7.75-8.05 (m, 10H).

Example 2 1- (Benzoyloxymethoxy)methyl!thymine (2) ##STR25##

A. A suspension of thymine (12.6 g, 0.1 mole), ammonium sulfate (300 mg)and trimethylsilyl chloride (2.5 mL) in hexamethyldisilazane (150 mL)was heated at 140° C. for 16 hr under nitrogen. The volatiles wereremoved in vacuo at 50° C. and the residual oil was dissolved in xylene(30 mL) and concentrated to dryness.

B. To a solution of the silylated thymine in CH₂ Cl₂ (200 mL) was addedbisbenzoyloxymethyl ether (30 g, 0.1 mol) and trimethylsilyltrifluoromethanesulfonate (50 mL). The solution was stirred for 8 hr at25° C. under nitrogen. The reaction was diluted with ethyl acetate (400mL) and washed with aqueous sodium carbonate, brine, dried (MgSO₄),filtered and concentrated in vacuo. The crude oily material was purifiedby silica gel column chromatography using CH₂ Cl₂ /5% MeOH as eluent togive the title compound as white crystals: yield 14.5 g (50%); m.p.141°-143° C.

Analysis: Calcd. for C₁₄ H₁₄ N₂ O₅ : C, 57.93; H, 4.82; N, 9.65. Found:C, 57.59; H, 4.90; N, 9.52.

¹³ C-NMR (50.3 MHz, DMSO-d₆): δ 70.779, 72.477, 72.915, 73.349, 82.985,105.563, 123.376, 124.076, 24.368, 128.383, 134.397, 146.260, 159.451,160.211.

¹ H-NMR (CDCl₃): δ 1.82 (s, 3H), 5.38 (s, 2H), 5.62 (s, 2H), 7.10 (s,1H), 7.4-8.0 (m, 5H).

Example 3 1- (Diethylphosphonomethoxy)methoxymethyl!thymine (3)##STR26##

To a solution of 1- (benzoyloxy)methoxymethyl!thymine (2.9 g, 10 mmol)and diethyl phosphonomethanol (1.85 g, 11 mmol) in benzene (180 mL) wasadded trimethylsilyl trifluoromethanesulfonate (0.05 mL) via a syringeunder nitrogen. The solution was heated at 85° C. for 20 min. Aftercooling to room temperature, ethyl acetate (50 mL) was added and washedwith aqueous bicarbonate, brine dried (MgSO₄), filtered and concentratedin vacuo. The resultant yellow oil was purified by silica gel columnchromatography using CH₂ Cl₂ /5% MeOH as an eluent to give the titlecompound as a white oil: yield 980 mg (30%).

¹ H-NMR (200 MHz, CDCl₃): δ 1.39 (t, J=6.6 Hz, 6H), 1.98 (s, 3H), 3.85(d, J=9.9 Hz, 2H), 4.1-4.3 (m, 4H), 4.82 (s, 2H), 5.20 (s, 2H), 7.20 (s,1H), 9.0 (bs, 1H).

Example 4 1- 3-(Ethylphosphonomethoxy)methyloxymethyl)!thymine sodiumsalt (4) ##STR27##

A solution of 1- (diethylphosphonomethoxy)methoxymethyl!thymine (400 mg,1.2 mmol) in 1N NaOH (8 mL) was stirred for 3 hr at 25° C. The solutionwas concentrated in vacuo and the resultant solid was purified by C₁₈reverse phase column chromatography using water as an eluent under 8 psipressure. The fractions having ultraviolet absorption were checked withHPLC, combined and lyophilized to give the title compound as a whiteamorphous powder: yield 220 mg (55%).

Analysis: Calcd. for C₁₀ H₁₆ N₂ O₇ PNa.H₂ O: C, 34.48; H, 5.17; N, 8.05.Found: C, 34.92; H, 5.37; N, 8.35.

UV_(max) (H₂ O): 226 nm (ε=6966).

¹³ C-NMR (50.3 MHz, D₂ O): δ 11.451, 15.843, 61.067, 61.826, 63.585,75.247, 94.631, 111.049, 141.277, 155.20, 170.907.

¹ H-NMR (200 MHz, D₂ O): δ 1.19 (t, J=6.8 Hz, 3H), 1.81 (s, 3H), 3.62(d, J=8.9 Hz, 2H), 3.8-4.1 (m, 2H), 3.62 (s, 2H), 4.78 (s, 2H), 5.20 (s,2H), 7.45 (s, 1H).

Example 5 1- (Phosphonomethoxy)methoxymethyl!thymine disodium salt (5)##STR28##

To a solution of 1- 3-(ethylphosphonomethoxy)methoxymethyl!thyminesodium salt (300 mg, 0.9 mmol) in dry DMF (5 mL) was addedbromotrimethylsilane (1.5 mL) under nitrogen. After stirring 3 hr at 25°C., volatiles were removed in vacuo and the residue was dissolved inaqueous saturated bicarbonate and re-evaporated in vacuo to a solidfoam. Purification of this material by a C₁₈ reverse phase columnchromatography using water as eluent under 8 psi pressure andlyophilization of combined fractions gave the title compound as a whiteamorphous foam: Yield 140 mg (48%).

Analysis: Calcd. for C₈ H₁₁ N₂ O₇ PNa₂ : C, 29.64; H, 3.42; N, 8.64.Found: C, 29.91; H, 3.61; N, 9.16.

UV_(max) (H₂ O): 266 nm (ε=8100).

¹ H-NMR (200 MHz, D₂ O): δ 1.75 (s, 3H), 3.27 (d, J=8.5 Hz, 2H), 4.71(s, 2H), 5.11 (s, 2H), 7.74 (s, 1H).

Example 6 2-Amino-6-chloro-9-(diethylphosphonomethoxy)methoxymethyl!purine (6) ##STR29##

To a suspension of 60% sodium hydride in mineral oil (1.4 g, 34.5 mmol)in n-pentane (100 mL) at 0° C. was added dropwise diethyl phosphate (4.4mL, 34.5 mmol) under nitrogen. After stirring for 1 hr at 0° C., asolution of bis(chloromethoxy)methane (25 g, 172 mmol) preparedaccording to the literature procedure: P. R. Strapp, J. Org. Chem., 34,1143 (1969)! in n-pentane (50 mL) was added at -70° C. The mixture wasstirred for 90 min at 0° C., and then the solvent was evaporated underreduced pressure. The residual oil was dissolved in xylene and volatileswere removed in vacuo to give crudechloromethoxy(diethoxyphosphonomethoxy)methane. Without furtherpurification, this material was used for the next reaction.

To a suspension of 60% sodium hydride in mineral oil (1.4 g, 34.5 mmol)in DMF (100 mL) was added 2-amino-6-chloropurine (5.78 g, 34.2 mmol) andthe mixture was stirred for 1 hr at 25° C. To the resulting yellowsolution was added dropwise a solution of abovechloromethoxy(diethylphosphonomethoxy)methane in DMF (20 mL) undernitrogen. After stirring 15 hr at 25° C., volatiles were removed invacuo. The residual oil was suspended in ethyl acetate (100 mL), washedwith water (30 mL), brine and dried (MgSO₄). The solvent was removedunder reduced pressure, and the residual oil was chromatographed onsilica gel using CH₂ Cl₂ /3% MeOH as eluent to give the title compoundas a colorless oil: yield 3.0 g (23%).

¹ H-NMR (300 MHz, CDCl₃): δ 1.395 (t, J=6.9 Hz, 6H), 3.850 (d, J=9.0 Hz,2H), 4.05-4.20 (m, 4H), 4.697 (s, 2H), 5.323 (bs, 2H), 5.578 (s, 2H),7.889 (s, 1H).

Example 7 9- (Methylphosphonomethoxy)methoxymethyl!guanine sodium salt(7) ##STR30##

To a solution of 2-amino-6-chloro-9-3-(diethylphosphonomethoxy)methoxymethyl!purine (325 mg, 0.84 mmol) inmethanol (5 mL) was added 1N sodium methoxide in methanol (10 mL). Thesolution was heated at 80° C. for 1 hr under nitrogen. Volatiles wereremoved under reduced pressure. The residual oil was then dissolved inwater (10 mL) and the solution was heated at 100° C. for 1 hr. The pH ofthe solution was carefully adjusted to 8.0 at 0° C. by dropwise additionof 1N HCl. Water was then evaporated in vacuo and the residual oil waspurified by a reverse phase column using water as eluent to give thetitle compound as a white solid: yield 185 mg (60%).

UV_(max) (H₂ O): 254 nm (ε=14,372), 274 nm (ε=9,788).

¹³ C-NMR (75.47 MHz, D₂ O): δ 51.875, 60.464, 63.627, 70.005, 94.711,94.952, 116.171, 139.925, 151.665, 154.428, 159.278.

¹ H-NMR (300 MHz, D₂ O): δ 3.677 (d, J=10.3 Hz, 3H), 3.620 (d, J=9.0 Hz,2H), 4.817 (s, 2H), 5.539 (s, 2H), 7.882 (s, 2H).

Example 8 9- 3-(Phosphonomethoxy)methoxymethyl!guanine disodium salt (8)##STR31##

To a solution of 9- (methylphosphonomethoxy)methoxymethyl!guanine (1.5g, 4.4 mmol) in DMF (5 mL) was added bromotrimethylsilane (5 mL) undernitrogen. After stirring 3 hr at 25° C., the volatiles were removed invacuo and the residue was neutralized to pH 8.0 by addition of aqueoussaturated sodium bicarbonate. Water was then evaporated in vacuo, andthe residue was purified by a C₁₈ reverse phase column using water aseluent under 8 psi pressure to give the title compound as a whitepowder: yield 900 mg (59%).

UV_(max) (H₂ O): 252 nm (ε=12,113), 274 nm (ε=8,201).

¹³ C-NMR (75.47 MHz, D₂ O): δ 67.016, 69.018, 70,746, 95.680, 95.831,118.192, 141.812, 153.576, 157.386, 162.493.

¹ H-NMR (300 MHz, D₂ O): δ 3.525 (d, J=8.9 Hz, 2H), 4.766 (s, 2H), 5.539(s, 2H), 7.892 (s, 1H).

Example 9 9- (Diethylphosphonomethoxy)methoxymethyl!adenine (9)##STR32##

To a suspension of 60% sodium hydride in mineral oil (1.4 g, 34.5 mmol)in DMF (100 mL) was added adenine (4.7 g, 34.5 mmol) and the mixture wasstirred at 80° C. for 1 hr. To the resulting yellow solution was addeddropwise a solution of chloromethoxy(diethoxyphosphinomethoxy)methane(prepared from diethylphosphate (4.4 mL, 34.5 mmol) andbis(chloromethoxy)methane (25 g, 172 mmol)! in DMF (20 mL) undernitrogen. After stirring at 25° C. for 15 hr, volatiles were removed invacuo, and the resulting oily residue was purified by silica gel columnchromatography using CH₂ Cl₂ /10% MeOH as eluent to obtain the titlecompound as a colorless oil: yield 6.0 g (50%).

¹ H-NMR (300 MHz, CDCl₃): δ 1.390, (t, J=6.7 Hz, 6H), 3.821 (d, J=9.2Hz, 2H), 4.05-4.18 (m, 4H), 4.785 (s, 2H), 5.690 (s, 2H), 6.20 (bs, 2H),7.921 (s, 1H), 8.295 (s, 1H).

Example 10 9- 3-(Phosphonomethoxy)methoxymethyl!adenine disodium salt(10) ##STR33##

To a solution of 9- (diethylphosphonomethoxy)methoxymethyl!adenine (600mg, 1.7 mmol) in DMF (4 mL) was added bromotrimethylsilane (5 mL) undernitrogen. After stirring 3 hr at 25° C., the volatiles were removed invacuo and the residue was neutralized to pH 8.0 by addition of aqueoussaturated sodium bicarbonate. Water was then evaporated in vacuo, andthe residue was purified by a C₁₈ reverse phase column using water aseluent under 8 psi pressure to give the title compound as a whitepowder: yield 280 mg (50%).

Analysis: Calcd. for C₈ H₁₀ N₅ O₅ PNa₂ (3H₂ O+0.2 mol NaCl): C, 22.08;H, 4.72; N, 16.10. Found: C, 22.15; H, 4.64; N, 16.26.

UV_(max) (H₂ O): 260 nm (ε=12,016)

hu 13C-NMR (75.47 MHz, D₂ O): δ 66.913, 68.917, 71.033, 95.729, 95.940,120.228, 144.611, 150.754, 154.766, 157.370.

¹ H-NMR (300 MHz, D₂ O): δ 3.486 (d, J=8.9 Hz, 2H), 4.779 (s, 2H), 5.710(s, 2H), 8.177 (s, 1H), 8.226 (s, 1H).

Example 11 1- (Diethylphosphonomethoxy)methoxymethyl!cytosine (11)##STR34##

To a suspension of 60% sodium hydride in mineral oil (700 mg, 17 mmol)in DMF (50 mL) was added cytosine (1.9 g, 17 mmol) and the mixture washeated at 80° C. for 2 hr under nitrogen. To the resulting yellowsolution was added dropwise a solution ofchloromethoxy(diethylphosphonomethoxy)methane prepared fromdiethylphosphate (2.4 g, 17 mmol) and bis-(chloromethoxy)methane (12.5g, 86 mmol)! in DMF (10 mL) under nitrogen. After stirring 15 hr at 25°C., the volatiles were removed in vacuo. The residue was dissolved inethyl acetate (120 mL) and water (30 mL). The organic phase was washedwith brine and dried (MgSO₄). After removal of the solvent in vacuo, theresidual oil was chromatographed on silica gel using CH₂ Cl₂ /10% MeOHas eluent to give the title compound as a white oil: yield 1.2 g (22%).

¹ H-NMR (300 MHz, CDCl₃): δ 1.390 (t, J=6.9 Hz, 6H), 1.90 (bs, 2H),3.815 (d, J=9.0 Hz, 2H), 4.05-4.20 (m, 4H), 4.752 (s, 2H), 5.20 (s, 1H),5.853 (d, J=7.4 Hz, 1H), 7.312 (d, J=7.4 Hz, 1H).

Example 12 1- (Phosphonomethoxy)methoxymethyl!cytosine disodium salt(12) ##STR35##

To a solution of 1- diethylphosphonomethoxy)methoxymethyl!cytosine (1.2g, 3.7 mmol) in DMF (5 mL) was added bromotrimethylsilane (5 mL) undernitrogen. After stirring 3 hr at 25° C., the volatiles were removed invacuo and the residue was neutralized to pH of 8.0 by the addition ofaqueous saturated sodium bicarbonate. Water was then evaporated in vacuoand the residue was purified by a C₁₈ reverse phase column using wateras eluent under 8 psi pressure to give the title compound as a whitesolid: yield 460 mg (47%).

Analysis: Calcd. for C₇ H₁₁ N₃ O₆ PNa₂ (3 H₂ O+5% NaCl); C, 21.99; H,4.22; N, 10.99. Found: C, 21.72; H, 4.65; N, 10.78.

UV_(max) (H₂ O): 268 nm (ε=8,245)

¹³ C-NMR (75.47 MHz, D₂ O): δ 66.876, 68.873, 77.710, 96.141, 96.284,98.178, 148.355, 160.409, 162.543.

¹ H-NMR (300 MHz, D₂ O): δ 3.560 (d, J=9.0 Hz, 2H), 4.849 (s, 2H), 5.313(s, 2H), 6.03 (d, J=7.3 Hz, 1H), 7.714 (d, J=7.3 Hz, 1H).

Example 13 2-(Phenylselenyl)ethoxy!methylchloride (13) ##STR36##

To a solution of 2-(phenylselenyl)ethanol (4.0 g, 20 mmol) preparedaccording to the literature procedure: P. Rollin, V. V. Bencomo, P.Sinay, Synthesis, 13 (1984)! in CH₂ Cl₂ (15 mL) was addedparaformaldehyde (620 mg, 20 mmol). HCl gas was then bubbled into thesolution at 5° C. for 2 hr. The solution was dried (MgSO₄), and thesolvent was removed under reduced pressure to give the title compound asa colorless oil in a quantitative yield.

¹ H-NMR (300 MHz, CDCl₃ : δ 3.059 (t, J=7.0 Hz, 2H), 3.882 (t, J=7.0 Hz,2H), 5.449 (s, 2H), 7.2-7.5 (m, 5H).

Example 14 2-Amino-6-chloro-9- (2-phenylselenyl)ethoxymethyl!purine (14)##STR37##

A mixture of 2-amino-6-chloropurine (20 g, 118 mmol) and ammoniumsulfate (400 mg) in hexamethyldisilazane (400 mL) andchlorotrimethylsilane (6 mL) was heated at 145° C. for 5 hr undernitrogen. Volatiles were removed in vacuo and the residue was evaporatedwith xylene twice, and further dried in vacuo for 3 hr. The crudesilylated 2-amino-6-chloropurine (15 g, 72 mmol) and mercuric cyanide(15 g, 59 mmol) in benzene (900 mL) was heated at reflux for 30 min,then a solution of 2-(phenylselenyl)ethoxymethylchloride (17 g, 68 mmol)in benzene (100 mL) was added. The mixture was refluxed for 3 hr, andthen allowed to stir for 15 hr at 25° C. The reaction was diluted withCH₂ Cl₂ (300 mL), and quenched with aqueous saturated bicarbonate (2 L).The organic phase was washed with 2N potassium iodide (200 mL), dried(MgSO₄), and the solvents were removed in vacuo. The residual oil waschromatographed on silica gel using CH₂ Cl₂ /5% MeOH as eluent toprovide the title compound as a slightly yellow foam: yield 15.0 g(63%).

Analysis: Calcd. for C₁₄ H₁₄ N₅ OClSe.1/2 H₂ O; C, 42.93; H, 3.86; N,17.88. Found: C, 42.92: H, 3.80: N, 17.59

¹ H-NMR (300 MHz, CDCl₃): δ 2.961 (t, J=6.9 Hz, 2H), 3.704 (t, J=6.9 Hz,2H), 5.196 (bs, 2H), 5.420 (s, 2H), 7.1-7.4 (m, 5H), 7.806 (s, 1H).

¹³ C-NMR (75.47 MHz, CDCl₃): δ 26.041, 69.144, 72.710, 127.206, 128.653,128.846, 131.232, 136.062, 144.946, 151.190, 151.833, 152.298.

Example 15 2-Acetamido-6-chloro-9- (2-(phenylselenyl)ethoxymethyl!purine(15) ##STR38##

A solution of 2-amino-6-chloro-9- (2-phenylselenyl)ethoxymethyl!purine(8 g, 21 mmol) in acetic anhydride (80 mL) was heated at 55° C. for 40hr. Volatiles were removed in vacuo and the residual oil was purified bysilica gel column chromatography using CH₂ Cl₂ /40% EtOAc as eluent togive the title compound as a yellow powder: yield 5.8 g (65%).

Analysis: Calcd. for C₁₆ H₁₆ N₅ O₂ ClSe: C, 45.25: H, 3.80; N, 16.49.Found: C, 45.12; H, 3.90; N, 16.47.

¹ H-NMR (300 MHz, CDCl₃): δ 2.49 (s, 3H), 2.961 (t, J=6.9 Hz, 2H), 3.756(t, J=6.9 Hz, 2H), 5.541 (s, 2H), 7.2-7.4 (m, 5H), 8.063 (s, 1H).

Example 16 2-Acetamido-6-chloro-9-(vinyloxymethyl)purine (16) ##STR39##

To a solution of 2-acetamido-6-chloro-9-(2-(phenylselenyl)ethoxymethyl!purine (424 mg, 1 mmol) in methanol (20mL) was added sodium bicarbonate (92 mg, 1.1 mmol) and sodium periodate(320 mg, 1.5 mmol). After stirring at 25° C. for 30 min the mixture wasfiltered and evaporated to dryness. The residue was dissolved in dioxane(20 mL) and the solution was heated at 80° C. for 20 min under nitrogen.The solution was evaporated in vacuo and the residual oil waschromatographed on silica gel using CH₂ Cl₂ /20% MeOH as eluent to givethe title compound as a slightly yellow foam: yield 220 mg (60%).

Analysis: Calcd. for C₁₀ H₁₀ N₅ O₂ Cl: C, 44.88; H, 3.77; N, 26.17.Found: C, 44.57; H, 3.83; N, 25.82.

Example 17 2-Acetamido-6-chloro-9-(1-(dimethylphosphonomethoxy)ethoxy)methyl!purine (17) ##STR40##

To a solution of 2-acetamido-6-chloro-9-(vinyloxy)purine (2.2 g, 6.0mmol) and dimethylphosphonomethanol (1.67 g, 12.0 mmol) in chloroform(100 mL) was added 120 mg of methanesulfonic acid. After heating at 60°C. for 2 hr, the solvent was removed in vacuo and the residual oil waschromatographed on silica gel using CH₂ Cl₂ /10% MeOH as eluent to givethe title compound as a colorless oil: yield 1.2 g (50%).

¹³ C-NMR (75.47 MHz, CDCl₃): 18.794, 25.054, 53.064, 53.218, 55.743,59.056, 68.071, 99.254, 99.502, 127.921, 144.576, 151.598, 152.645,170.299.

¹ H-NMR (300 MHz, CDCl₃): δ 1.347 (d, J=8.1 Hz, 3H), 2.519 (s, 3H),3.852 (d, J=16.2 Hz, 6H), 5.029 (q, J=8.1 Hz, 1H), 5.648 (d, J=15.6 Hz,1H), 5.791 (d, J=15.6 Hz, 1H), 7.275 (s, 1H), 8.201 (s, 1H).

Example 18 9- (1-(Phosphonomethoxyethoxy)methyl!guanine disodium salt(18) ##STR41##

To a solution of 2-acetamido-6-chloro-9-(1-dimethylphosphonomethoxy)ethoxy)methyl!purine (1.2 g, 2.95 mmol) inmethanol (5 mL) was added 1N sodium methoxide in methanol (10 mL). Afterstirring at 25° C. for 1 hr, water (10 mL) was added and the solutionwas heated at 90° C. for 1 hr under nitrogen. Volatiles were removed invacuo and the residual oil was purified by C₁₈ reverse phase columnchromatography using water as eluent under 8 psi pressure. Each 10 mLfraction was assayed by high pressure liquid chromatography. Thecombined fractions were lyophilized to give a white solid. This materialwas dissolved in DMF (20 mL) followed by bromotrimethylsilane (5 mL).After stirring 2 hr at 25° C., volatiles were removed in vacuo and theresidue was purified by a C₁₈ reverse phase column using water as eluentunder 8 psi pressure to give the title compound as white amorphouspowder after lyophilization: yield 245 mg (24%).

Analysis: Calcd. for C₉ H₁₂ N₅ O₆ PNa₂.4H₂ O: C, 25.78, H, 4.80; N,16.70. Found: C, 25.93; H, 4.44; N, 16.91.

UV_(max) (H₂ O): 252 nm (ε=9751).

¹³ C-NMR (75.47 MHz, D₂ O): δ 20.859, 64.079, 66.088, 70.423, 102.054,102.241, 119.11, 140.287, 153.110, 162.211, 168.712.

¹ H-NMR (300 MHz, D₂ O): δ 1.195 (d, J=6.3 Hz, 3H), 3.305 (dd, J=8.9,8.4 Hz, 1H), 3.496 (dd, J=8.9, 8.4 Hz, 1H), 4.874, (q, J=6.3 Hz, 1H),5.475 (dd, J=14.0, 11.1 Hz, 1H), 5.523 (dd, J=14.0, 11.1 Hz, 1H), 7.790(s, 1H).

Example 19 1-(5-Methoxytetrahydro-2-furyl)thymine (19) ##STR42##

To a suspension of thymine (2.5 g, 20 mmol) in hexamethyldisilazane (30mL) was added ammonium sulfate (50 mg) and chlorotrimethylsilane (0.5mL) and the mixture was heated at 145° C. for 4 hr under nitrogen. Theexcess hexamethyldisilazane was removed at reduced pressure, and theresidual oil was dissolved in xylene and evaporated in vacuo to give acolorless viscous oil. To this silylated thymine in dichloroethane (40mL) was added 2,5-dimethoxytetrahydrofuran (7 mL). After cooling thesolution to -30° C., tin tetrachloride (2.3 mL) was added dropwise via asyringe under nitrogen. The mixture was allowed to warm to -10° C. andwas then poured into ice cold aqueous sodium bicarbonate (100 mL) andethyl acetate (150 mL). The mixture was filtered and the organic phasewas separated and dried (MgSO₄). The solvent was removed under reducedpressure and the residual oil was chromatographed on silica gel usingCH₂ Cl₂ /5% MeOH as eluent to give the title compound as a cis/transmixture in a ratio of 1:1 as shown by analytical HPLC and ¹ H-NMR: yield3.4 g (75%).

Analysis: Calcd. for C₁₀ H₁₄ N₂ O₄ : C, 53.08; H, 6.24; N, 12.39. Found:C, 52.81; H, 6.22; N, 12.38.

UV_(max) (EtOH): 266 nm (ε=9076).

¹ H-NMR (300 MHz, CDCl₃): δ 1.4-2.1 (m, 7H), 3.40 and 3.425 (two s, 3H),5.20 and 5.328 (two bs, 1H), 6.208 and 6.417 (two dd, J=3.5, 7.0 Hz and7.2, 7.2 Hz, 1H), 7.021 and 7.40 (bs, 1H).

The cis/trans (19A/19B) mixture was separated by a careful silica gelcolumn chromatography. Thus, the cis isomer 19A was eluted first withCH₂ Cl₂ /3% MeOH and obtained as a white needle. The X-raycrystallography and the NOE (Nuclear Overhauser Effect) NMR confirmedthe cis stereochemical arrangement of 19A. m.p. 153°-54° C.

Analysis: Calcd. for C₁₀ H₁₄ N₂ O₄ : C, 53.09; H, 6.24; N, 12.38. Found:C, 52.92; H, 6.20; N, 12.10.

¹³ C-NMR (75.47 MHz, CDCl₃): δ 12.634, 29.417, 32.157, 55.202, 105.883,111.411, 135.952, 139.553, 150.938, 163.906.

¹ H-NMR (300 MHz, CDCl₃): δ 1.950 (s, 3H), 1.9-2.3 (m, 4H), 3.40 (s,3H), 5.20 (t, J=2.9 Hz, 1H), 6.417 (dd, J=4.0, 7.2 Hz, 1H), 7.40 (s,1H), 8.781 (s, 1H).

Continuing the column with CH₂ Cl₂ /3% MeOH, the trans isomer 19B waseluted after the cis isomer 19A and was obtained as white needles. TheNOE observation of 19A was consistent with the assigned structure: m.p.124°-125° C.

Analysis: Calcd. for C₁₀ H₁₄ N₂ O₄ : C, 53.09; H, 6.24; N, 12.38. Found:C 53.10; H, 6.10; N, 12.00.

¹ H-NMR (75.47 MHz, CDCl₃): δ 1.920 (s, 3H), 2.0-2.5 (m, 4H), 3.425 (s,3H), 5.328 (dd, J=2.5, 6.0 Hz, 1H), 6.208 (dd, J=3.5, 7.0 Hz, 1H), 7.021(s, 1H), 8.885 (s, 1H).

Example 20 1-(4-Dimethylphosphonomethoxytetrahydro-2-furyl)thymine (20)##STR43##

To a solution of 1-(5-methoxytetrahydro-2-furyl)thymine (5.2 g, 23 mmol)and dimethylphosphonomethanol (6.5 g, 44 mmol) in toluene was addedacetic acid (5 mL) and p-toluenesulfonic acid monohydrate (500 mg, 2.6mmol). The solution was heated at 100° C. for 2 hr and the resultinginsoluble solid was removed by suction filtration. After removal of thesolvent under reduced pressure, the residual oil was chromatographed onsilica gel using CH₂ Cl₂ /5% MeOH as eluent to give the title compoundas a cis/trans mixture (6:4): yield 5.0 g (60%).

¹ H-NMR (300 MHz, CDCl₃): δ 1.9-2.2 (m, 1OH), 3.8-4.1 (m, 6H), 5.198,5.445 (bs, 0.6 and 0.4H), 6.250 (dd, J=2.8, 7.5 Hz, 0.4H), 6.437 (t,J=7.4 Hz, 0.6H), 7.052 (s, 0.4H), 7.405 (s, 0.6H), 9.60 (bs, 0.6H),7.628 (bs, 0.4H).

Example 21 1-(4-Methylphosphonomethoxytetrahydro-2-furyl)thymine sodiumsalt (21) ##STR44##

To a solution of 1-(4-dimethylphosphonomethoxytetrahydro-2-furyl)thymine(5 g, 14.6 mmol) in methanol (10 mL) was added 2N sodium hydroxide (20mL). After stirring 2 hr at 25° C., the reaction was neutralized to pH8.0 by addition of 3N HCl with stirring. Water was then evaporated invacuo and the residual oil was purified by a C₁₈ reverse phase columnusing water as eluent to give the title compound as a white powder. Thismaterial was shown to be a 1:1 cis/trans (21A/21B) mixture by analyticalHPLC and ¹ H-NMR: yield 3.2 g (65%).

Analysis: Calcd. for C₁₁ H₁₆ N₂ O₇ NaP.2H₂ O: C, 34.92; H, 5.29; N,7.40. Found: C, 34.93; H, 4.99; N, 7.43.

UV_(max) (H₂ O): 268 nm (ε=8668).

¹ H-NMR (300 MHz, D₂ O): δ 1.842 (s, 1.5H), 1.894 (s, 1.5H), 1.9-2.5 (m,4H), 3.571 (d, J=9.8 Hz, 1H), 3.589 (d, J=9.2 Hz, 1H), 3.59-3.85 (m,2H), 5.239 (d, J=3.5. Hz, 0.5H), 5.483 (d, J=4.7 Hz, 0.5H), 6.198 (q,J=2.9 Hz, 0.5H), 6.331 (t, J=6.0 Hz, 0.5H), 7.371 (s, 0.5H), 7.561 (s,0.5H).

The cis/trans mixture was separated by a C₁₈ reverse phase column (100time weight) using water/3% acetonitrile as eluent under 6 psigpressure. Each 15 mL fraction was assayed by HPLC. The cis isomer 21Awas eluted first and obtained as a white powder.

¹ H-NMR(300 MHz, D₂ O): δ 1.894 (s, 3H), 2.0-2.45 (m, 4H), 3.571 (d,J=9.8 Hz, 2H), 3.595 (dd, J=7.4, 10.0 Hz, 1H), 3.781 (dd, J=7.4, 10.8Hz, 1H), 5.239 (d, J=3.5 Hz, 1H), 6.331 (t, J=6.0 Hz, 1H), 7.561 (s,1H).

After cis/trans mixture fractions, the pure trans isomer 21B was alsoobtained as a white powder.

¹ H-NMR (300 MHz, D₂ O): δ 1.842 (s, 3H), 2.0-2.5 (m, 4H), 3.589 (d,J=9.2 Hz, 2H), 3.611 (dd, J=9.2, 10.0 Hz, 1H), 3.840 (dd, J=9.2, 10.0Hz, 1H), 5.483 (d, J=4.3 Hz, 1H), 6.198 (q, J=2.9 Hz, 1H), 7.371 (s,1H).

The steroechemical assignment of the cis and trans isomers was confirmedby the NOE (Nuclear Overhauser Effect) NMR.

Example 22 1-(4-Phosphonomethoxytetrahydro-2-furyl)thymine disodium salt(22) ##STR45##

To a solution of 1-(4-methylphosphonotetrahydro-2-furyl)thymine sodiumsalt (1.2 g, 3.5 mmol) in DMF (15 mL) was added bromotrimethylsilane (10mL) under nitrogen. After stirring 4 hr at 25° C., the volatiles wereremoved in vacuo and the residual oil was neutralized to pH 8.0 by theaddition of aqueous sodium bicarbonate. Water was then evaporated invacuo, and the residue was purified by a C₁₈ reverse phase column usingwater as eluent under 8 psi pressure to give the title compound as awhite powder: yield 857 mg (70%).

Analysis: Calcd. for C₁₀ H₁₃ N₂ O₇ PNa₂.5H₂ O: C, 27.26; H, 5.20; N,6.36. Found: C, 27.14; H, 5.26; N, 6.03.

UV_(max) (H₂ O): 268 nm (ε=7.350).

¹ H-NMR (300 MHz, D₂ O): δ 1.864 (s, 1.5H), 1.928 (s, 1.5H), 1.95-2.90(m, 4H), 3.4-3.6 (m, 2H), 5.363 (t, J=3.0 Hz, 0.5H), 5.56 (d, J=4.2 Hz,0.5H), 6.212 (dd, J=2.7, 5.8 Hz, 0.5H), 6.321 (t, J=3.9 Hz, 0.5H), 7.435(s, 0.5H), 7.679 (s, 0.5H).

Example 23 1-2,3-Dideoxy-4-β-chloro-3-(phenylselenyl)-β-D-erythrofuranosyl!thymine(23) ##STR46##

To a solution of1-(2,3-dideoxy-3,-4-didehydro-β-D-erythrofuranosyl)thymine (1.94 g, 10mmol) prepared according to the literature procedure: J. Zemlicka, R.Gasser, J. V. Freisler, J. P. Horwitz, J. Amer. Chem. Soc., 94, 3213(1972)! in CH₂ Cl₂ (30 mL) was added at -70° C. dropwise a solution ofphenylselenyl chloride (1.92 g, 10 mmol) in CH₂ Cl₂ (5 mL) undernitrogen. After stirring at -70° C. for 1 hr, the solvent was removed invacuo to give the title compound as a yellowish oil. This material wasused for the next reaction without further purification.

¹ H-NMR (300 MHz, CDCl₃): δ 1.95 (s, 3H), 2.5-2.8 (m, 2H), 4.18 (d,J=6.5 Hz, 1H), 6.20 (s, 1H), 6.55 (q, J=6.0, 7.5 Hz, 1H), 7.1-7.7 (m,6H), 9.30 (broad, 1H).

Example 24 1-2,3-Dideoxy-4-β-(dimethylphosphono)methoxy-3-(phenyselenyl)-β-D-erythrofuranosyl!thymine(24) ##STR47##

To a solution of 1-2,3-dideoxy-4-chloro-3-(phenylselenyl)-β-D-erythrofuranosyl!thymine(3.85 g, 10 mmol) and dimethoxyphosphinylmethanol (1.5 g, 11 mmol) inCH₂ Cl₂ (20 mL) was added dropwise at -70° C. a solution of silverperchlorate (2.3 g, 11 mmol) in CH₃ CN (3 mL) over 3 min under nitrogen.The mixture was allowed to warm to 0° C. and was then poured intoaqueous saturated bicarbonate (10 mL)-brine (15 mL). The organic phasewas separated after filtration and dried (MgSO₄). The solvents wereremoved under reduced pressure, and the residual oil was purified bysilica gel column chromatography using CH₂ Cl₂ /5% MeOH as eluent togive the title compound as a colorless oil: yield 1.3 g (31%).

¹ H-NMR (300 MHz, CDCl₃): δ 1.93 (s, 3H), 2.45 (m, 2H), 3.70 (dd, J=8.4,8.0 Hz, 1H), 3.75 (d, J=12.0 Hz, 6H), 3.85 (d, J=6.9 Hz, 1H), 3.90 (dd,J=8.4, 8.0 Hz, 1H), 5.10 (s, 1H), 6.52 (s, 1H), 7.35 (s, 1H), 8.86 (bs,1H).

Example 25 1-2,3-Dideoxy-2,3-didehydro-4-phosphonomethoxy-β-D-erythrofuranosyl!thyminedisodium salt (25) ##STR48##

To a solution of 1-2,3-dideoxy-4-(dimethylphosphono)methoxy-3-(phenylselenyl-β-D-erythrofuranosyl!thymine(1.15 g, 2.76 mmol) in DMF (4 mL) was added at 5° C.bromotrimethylsilane (3 mL) under nitrogen. After stirring for 4 hr at5° C., volatiles were removed in vacuo and the residue was dissolved inaqueous saturated bicarbonate (3 mL) and evaporated again in vacuo togive a slightly yellow solid.

¹ H-NMR (200 MHz, D₂ O): δ 1.79 (s, 3H), 2.3-2.5 (m, 2H), 3.27 (1,J=7.6, 8.4 Hz, 1H), 3.50 (1, J=7.6, 8.4 Hz, 1H), 3.93 (d, J=6.9 Hz, 1H),5.23 (s, 1H), 6.0 (t, J=6.9 Hz, 1H), 7.53 (s, 1H).

The reaction product from the above example was dissolved in water (5mL) followed by sodium periodate (1.7 g, 8.0 mmol). After stirring for30 min, the reaction mixture was heated at 80° C. for 8 min and thenfiltered. The filtrate was evaporated to dryness and the residual solidwas purified by a C₁₈ reverse phase column chromatography using water aseluent under 8 psi pressure. Each 15 mL fraction was assayed by highpressure liquid chromatography. Lyophilization of combined fractionsgave the title compound as a white amorphous solid: yield 538 mg (50%);m.p. 233°-237° C.

Analysis: Calcd. for C₁₀ H₁₁ N₂ O₇ Na₂ P.H₂ O: C, 32.61; H, 3.51; N,7.61. Found: C, 32.31; H, 3.63; N, 7.35.

¹³ C-NMR (50.3 MHz, D₂ O): δ 13.921, 67.870, 69.848, 89.868, 111.242,111.364, 113,908, 131.177, 134.,655, 139.350.

¹ H-NMR (300 MHz, D₂ O): δ 1.848 (s, 3H), 3.565 (dd, J=8.4, 8.7 Hz, 1H),3.738 (dd, J=8.4, 8.7 Hz, 1H), 5.987 (s, 1H), 6.180 (d, J=6.0 Hz, 1H),6.432 (d, J=6.0 Hz, 1H), 6.817 (s, 1H), 7.377 (s, 1H).

UV_(max) (H₂ O): 266 nm (ε=10,134). Example 26

1-2,3-Dideoxy-2,3-didehydro-4-β-(dimethylphosphono)methoxy-β-D-erythrofuranosyl)thymine(26) ##STR49##

To a solution of1-(2,3-dideoxy-4-β-(dimethylphosphono)methoxy-3-(phenylselenyl)-.beta.-D-erythrofuranosyl!thymine(6.0 g, 12.2 mmol) in methanol (20 mL) was added dropwise a suspendedsolution of sodium bicarbonate (1.8 g, 21 mmol) and sodium periodate(3.2 g, 15 mmol) in water (20 mL). After stirring at 25° C. for 1 hr,the mixture was heated at 80° C. for 60 min. Volatiles were removed invacuo and the residue was suspended in CH₂ Cl₂ (120 mL). After removalof insoluble material, the organic phase was dried (MgSO₄) andevaporated in vacuo. The residue was chromatographed on silica gel usingCH₂ Cl₂ /5% MeOH as eluent to give the title compound as a whiteamorphous powder: yield 3.4 g (85%).

Analysis: Calcd. for C₁₂ H₁₇ N₂ O₇ P: C, 43.38; H, 6.16; N, 8.43. Found:C, 43.53; H, 5.20; N, 8.26.

¹³ C-NMR (75.47 MHz, CDCl₃): δ 12.339, 52.889, 52.976, 53.080, 60.491,62.738, 87.837, 108.402, 108.569, 111.653, 130.613, 131.675, 135.435,150.480, 163.503.

¹ H-NMR (300 MHz, CDCl₃): δ 1.862 (s, 3H), 3.748 (d, J=12.8 Hz, 3H),3.814 (d, J=12.8 Hz, 1H), 3.826 (dd, J=8.9, 8.4 Hz, 1H), 3.902 (dd,J=8.9, 8.4 Hz, 1H), 5.711 (s, 1H), 6.075 (d, J=5.7 Hz, 1H), 6.233 (d,J=5.7 Hz, 1H), 6.915 (s, 1H), 7.129 (s, 1H), 8.95 (bs, 1H).

Example 27 1-2,3-Dideoxy-2,3-didehydro-4-β-(methylphosphono)methoxy-β-D-erthyrofuranosyl!thyminesodium salt (27) ##STR50##

A solution of 1-2,3-dideoxy-2,3-dihydro-4-β-(dimethylphosphono)methoxy-β-D-2-erythrofuranosyl!thymine(180 mg, 0.54 mmol) in 1N NaOH (2 mL) was stirred at 25° C. for 2 hr.The reaction was carefully neutralized to pH 8.0 by dropwise addition of1N HCl with good stirring. Water was then evaporated in vacuo and theresidue was purified by a C₁₈ reverse phase column using water/3%acetonitrile as eluent to give the title compound as a white solid:yield 125 mg (68%).

Analysis: Calcd. for C₁₁ H₁₄ N₂ O₇ PNa.1.5 H₂ O: C, 34.28; H, 4.93; N,7.27. Found: C, 34.02; H, 49.4; N, 7.19.

UV_(max) (H₂ O): 269 nm (ε=8160)

¹ H-NMR (300 MHz, D₂ O): δ 1.847 (s, 3H), 3.525 (d, J=11.0 Hz, 3H),3.917 (dd, J=13.6, 17.0 Hz, 1H), 3.765 (dd, J=13.6, 17.0 Hz, 1H), 5.849(s, 1H), 6.198 (d, J=4.6 Hz, 1H), 6.415 (d, J=4.6 Hz, 1H), 6.847 (s,1H), 7.374 (s, 1H).

Example 28 1-2,3-Dideoxy-4-β-(methylphosphono)methoxy-β-D-erythrofuranosyl!thyminesodium salt (28) ##STR51##

To a solution of 1-2,3-dideoxy-2,3-didehydro-4-β-(methylphosphono)methoxy-β-D-erythrofuranosyl!thyminesodium salt (300 mg, 0.9 mmol) in water (20 mL) was added 10% palladiumon active carbon (200 mg) and hydrogenated for 30 min under 35 psi H₂pressure. The catalyst was filtered and washed with methanol (30 mL).The combined filtrate and wash was evaporated in vacuo and the residuewas purified by a C₁₈ reverse phase column using water/2% acetonitrileunder 8 psi pressure to give the title compound as a white solid: yield250 mg (84%).

This material showed an identical nmr with compound 21A which wasprepared from 2,5-dimethoxytetrahydrofuran and the stereochemicalassignment of compound 21A was confirmed by the NOE.

¹ H-NMR (300 MHz, D₂ O): δ1.443 (s, 3H), 2.168 (m, 2H), 2.418 (m, 2H),3.608 (d, J=6.9 Hz, 3H), 3.68 (dd, J=13.5, 18.0 Hz, 1H), 3.85 (dd,J=13.5, 18.0 Hz), 5.303 (s, 1H), 6.390 (d, J=6.3 Hz, 1H), 7.627 (s, 1H).

In a manner similar to the above Example 28, the thymine-containingreactant can be replaced with a corresponding adenine, guanine orcytosine reactant to produce 1-2,3-dideoxy-2,3-didehydro-4-β-(methylphosphono)methoxy-β-D-erythrofuranosyl!adeninesodium salt, or 1-2,3-dideoxy-2,3-didehydro-4-β-(methylphosphono)methoxy-β-D-erythrofuranosyl!guaninesodium salt, or 1-2,3-dideoxy-2,3-didehydro-4-β-(methylphosphono)-methoxy-β-D-erythrofuranosylcytosine sodium salt.

Example 29 1-4-β-(Dimethylphosphono)methoxy-β-D-erythrofuranosyl!thymine (29)##STR52##

To a solution of 1-2,3-dideoxy-2,3-didehydro-4-β-(dimethylphosphono)methoxy-β-D-erythro-furanosyl!thymine(3.31 g, 10 mmol) in pyridine (20 mL) was added osmium tetroxide (2.54g, 10 mmol) at 0° C. and stirred for 2 hr. The solvent was removed invacuo. The residue was dissolved in ethyl acetate (100 mL), washed with10% phosphoric acid (30 mL), water (20 mL), aqueous sodium bicarbonate(20 mL), brine and dried MgSO₄). The solvent was removed in vacuo, andthe residual oil was chromatographed on silica gel using CH₂ Cl₂ /5%MeOH as eluent to give the title compound as a white powder: yield 2.56g (70%).

Analysis: Calcd. for C₁₂ H₁₉ N₂ O₉ P: C, 39.35; H, 5.23; N, 7.65. Found:C, 38.98; H, 5.09; N, 7.42.

¹³ C-NMR (75.47 MHz, DMSO-d₆): δ 11.861, 52.672, 52.797, 59.114, 61.411,72.608, 73.316, 73.399, 87.419, 107.607, 107.863, 110.810, 135.217,150.973, 163.581.

¹ H-NMR (300 MHz, DMSO-d₆): δ 1.675 (s, 3H), 3.540 (d, J=10.5 Hz, 6H),3.736 (1, J=4.0 Hz, 1H), 3.817 (d, J=9.6 Hz, 2H), 4.03 (dd, J=6.0, 11.2Hz, 1H), 4.763 (s, 1H), 5.35 (d, J=4.0 Hz, 1H), 5.45 (d, J=7.0 Hz, 1H),5.919 (d, J=6.9 Hz, 1H), 7.128 (s, 1H), 11.228 (bs, 1H).

In a manner similar to the above Example 29, the 15 thymine-containingreactant can be replaced with a corresponding adenine, guanine orcytosine reactant to produce 9-4-β-(dimethylphosphono)methoxy-β-D-erythrofuranosyl!adenine, or 9-4-β-(dimethylphosphono)methoxy-β-D-erythrofuranosyl!guanine, or 1-4-β-(dimethylphosphono)methoxy-β-D-erythrofuranosyl!cytosine.

Example 30 1- 4-(Methylphosphono)methoxy-β-D-erythrofuranosyl!thyminesodium salt (30) ##STR53##

To a solution of 1-4-β-(dimethylphosphonomethoxy-β-D-erythrofuranosyl!thymine (200 mg, 0.5mmol) in 1N NaOH (2 mL) was stirred at 25° C. for 2 hr. The reaction wascarefully neutralized to pH 9.0 by dropwise addition of 1N HCl withstirring. Water was then evaporated in vacuo and the residual oil waspurified by a C₁₈ reverse phase column using water/2% acetonitrile aseluent under 8 psi pressure to give the title compound as a whiteamorphous powder: yield 114 mg (56%).

Analysis Calcd. for C₁₁ H₁₅ N₂ O₉ PNa.2H₂ O: C, 32.27; H, 4.64; N, 6.84.Found: C, 31.94; H, 4.32; N, 6.86.

UV_(max) (H₂ O): 268 nm (ε=8153).

¹³ C-NMR (75.47 MHz, D₂ O): δ 35.644, 35.719, 45.366, 47.479, 57.032,57.411, 71.915, 92.426, 92.599, 96.463, 120.503, 137.007, 144.422,151.377.

¹ H-NMR (300 MHz, D₂ O): δ 1.922 (s, 3H), 3.615 (d, J=10.1 Hz, 3H),3.687 (dd, J=11.3, 11.1 Hz, 1H), 3.885 (dd, J=11.3, 11.1 Hz, 1H), 4.220(d, J=4.3 Hz, 1H), 4.574 (dd, J=6.7, 4.3 Hz, 1H), 5.09 (s, 1H), 6.175(d, J=6.7, Hz, 1H), 7.485 (s, 1H).

In a manner similar to the above Example 30, the thymine-containingreactant can be replaced with a corresponding adenine, guanine orcytosine reactant to produce 1-4-β-(methylphosphono)methoxy-β-D-erythrofuranosyl!adenine, or 1-4-β-(methylphosphono)methoxy-β-D-erythrofuranosyl!guanine, or 9-4-β-(methylphosphono)methoxy-β-D-erythrofuranosyl!cytosine.

Example 31 1-(4-β-Phosphonomethoxy-β-D-erythrofuranosyl)thymine disodiumsalt (31) ##STR54##

To a solution of 1- 4-62-(dimethylphosphono)methoxy-β-D-erythrofuranosyl!thymine (320 mg, 0.87mmol) in DMF (2 mL) was added at 0° C. bromotrimethylsilane (1.4 mL)under nitrogen. After stirring 90 min at 0° C., volatiles were removedin vacuo and the residue was neutralized to pH 8.0 by addition ofaqueous saturated sodium bicarbonate. Water was then evaporated in vacuoand the residual solid was purified by a C₁₈ reverse phase column usingwater/2% acetonitrile as eluent to give the title compound as a whitesolid: yield 153 mg (46%), m.p.>250° C. (dec.).

Analysis: Calcd. for C₁₀ H₁₃ N₂ O₉ PNa.2H₂ O: C, 27.52; H, 4.35; N,6.42. Found: C, 27.05; H, 3.99; N, 6.12.

UV_(max) (H₂ O): 268 nm (ε=7,568).

¹³ C-NMR (75.47 MHz, D₂ O): δ 49.590, 51.582, 57.347, 57.541, 71.861,93.034, 93.169, 95.541, 121.178, 136.393, 144.222, 150.601.

¹ H-NMR (300 MHz, D₂ O): δ 1.936 (s, 3H), 3.469 (dd, J=12.3, 12.6 Hz,1H), 3.756 (dd, J=12.3, 12.6 Hz, 1H), 4.258 (d, J=4.5 Hz, 1H), 4.578(dd, J=4.5, 6.2 Hz, 1H), 5.175 (s, 1H), 6.182 (d, J=6.2 Hz, 1H), 7.591(s, 1H).

In a manner similar to the above Example 31, the thymine-containingreactant can be replaced with a corresponding adenine, guanine orcytosine reactant to produce9-4-β-phosphonomethoxy-β-D-erythrofuranosyl!adenine disodium salt, or 9-4-β-phosphonomethoxy-β-D-erythrofuranosyl!guanine disodium salt, or 1-4-β-phosphonomethoxy-β-D-erythrofuranosyl!cytosine disodium salt.

Example 32 1-2-Deoxy-4-β-(diethylphosphono)methoxy-β-D-erythrofuranosyl!thymine (32A)and the trans isomer ##STR55##

To a solution of1-(2,3-dideoxy-3,4-didehydro-β-D-erythrofuranosyl)thymine (2.4 g, 12.4mmol) and diethylphosphonomethanol (17.4 g, 103 mmol) in CH₂ Cl₂ (2 mL)was added 80-85% 3-chloroperoxybenzoic acid (17.4 g, 13.14 mmol) at 5°C. After stirring for 60 min at 25° C., the reaction mixture waspurified by column chromatography on silica gel using CH₂ Cl₂ /3% MeOHto obtain the crude product, which was carefully rechromatographed onsilica gel to separate the two isomers. Using CH₂ Cl₂ /1% MeOH, theminor isomer B was first eluted and obtained as a colorless oil: yield75 mg (1.7%).

¹ H-NMR (300 MHz, CDCl₃) of 32B: δ 1.287 (t, J=6.9 Hz, 6H), 1.900 (s,3H), 1.97-2.58 (m, 2H), 3.807 (dd, J=9.0, 13.8 Hz), 4.016 (dd, J=9.0,13.8 Hz, 1H), 4.138 (m, 4H), 4.30 (m, 1H), 4.934 (d, J=4.2 Hz, 1H),6.321 (t, J=6.6 Hz, 1H), 7.417 (s, 1H), 9.80 (bs, 1H).

The silica gel column was continuously eluted with CH₂ Cl₂ /3% MeOH toobtain the major isomer 32A as a colorless oil: yield 735 mg (17%).

¹ H-NMR (300 MHz, CDCl₃) of 32A: δ 1.310 (t, J=7.5 Hz, 6H), 1.872 (s,3H), 1.95 (m, 1H), 2.70 (m, 1H), 3.780 (dd, J=9.3, 13.8 Hz, 1H), 3.928(dd, J=9.3, 13.8 Hz, 1H), 4.139 (m, 4H), 4.330 (d, J=5.7 Hz, 1H), 5.268(s, 1H), 6.238 (dd, J=2.7, 8.4 Hz, 1H), 7.624 (s, 1H), 9.176 (bs, 1H).

The stereochemical assignment of 32A and 32B was consistent with nmr NOEobservation.

In a manner similar to the above Example 32,1-(2,3-deoxy-3,4-didehydro-β-D-erythrofuranosyl)thymine can be replacedwith a corresponding adenine, guanine or cytosine reactant to produce 9-2-deoxy-4-β-(diethylphosphono)methoxy-β-D-erythrofuranosyl!adenine, 9-2-deoxy-4-β-(methylphosphono)methoxy-β-D-erythro-furanosyl!adeninesodium salt, or 9-2-deoxy-4-β-(diethylphosphono)methoxy-β-D-erythrofuranosyl!guanine, or1- 2-deoxy-4-β-(diethylphosphono)methoxy-β-D-erythrofuranosyl!cytosine.

Example 33 1-(2-Deoxy-4-β-phosphonomethoxy-β-D-erythrofuranosyl)thyminedisodium salt (33) ##STR56##

To a solution of 1-2-deoxy-4-(diethylphosphono)methoxy-β-D-erythrofuranosyl!thymine (480mg, 1.3 mmol) in DMF (2 mL) was added bromotrimethylsilane (2 mL) undernitrogen. After stirring 3 hr at 25° C., volatiles were removed in vacuoand the residue was carefully neutralized to pH 8.5 by addition ofaqueous saturated sodium bicarbonate. Water was evaporated to drynessand the residual solid was purified by a C₁₈ reverse phase column usingwater/3% acetonitrile as a eluent to give the title compound as a whitepowder: yield 165 mg (40%).

Analysis: Calcd. for C₁₀ H₁₃ N₂ O₈ PNa₂.3H₂ O: C, 28.57; H, 4.52; N,6.67. Found: C, 28,48; H, 4.49; N, 6.52.

UV_(max) (H₂ O): 268 nm (ε=7,602).

¹³ C-NMR (75.47 MHz, D₂ O): δ 20.803, 48.289, 50.291, 56.714, 69.570,94.015, 94.157, 94.994, 122.321, 135.750, 150.715.

¹ H-NMR (300 MHz, D₂ O): δ 1.853 (s, 3H), 1.924 (dd, J=2.6, 13.4 Hz,1H), 2.8-2.85 (dd, J=2.6, 5.3, 8.0 Hz, 1H), 3.415 (dd, J=8.9, 12.4 Hz,1H), 3.669 (dd, J=8.9, 12.4 Hz, 1H), 4.372 (d, J=5.3 Hz, 1H), 4.372 (d,J=5.3 Hz, 1H), 4.372 (d, J=5.3 Hz, 1H), 5.310 (s, 1H), 6.285 (dd, J=2.6,8.0 Hz, 1H), 7.776 (s, 1H).

In a manner similar to the above Example 33, the thymine-containingreactant can be replaced with a corresponding adenine, guanine orcytosine reactant to produce9-(2-deoxy-4-β-phosphonomethoxy-β-D-erythrofuranosyl)adenine disodiumsalt, or 9-(2-deoxy-4-β-phosphonomethoxy-β-D-erythrofuranosyl)guaninedisodium salt, or1-(2-deoxy-4-β-phosphonomethoxy-β-D-erythrofuranosyl)cytosine disodiumsalt.

Example 34 2-Acetamido-6-diphenylcarbamoyloxy-9-2-(phenylselenyl)ethoxymethyl!purine (34) ##STR57##

A mixture of 2-acetamido-6-diphenylcarbamoylpurine (36.7 g, 94.6 mmol)prepared according to the following literature procedure: R. Zou and M.J. Ropbins, Can. J. Chem., 65, No. 6, 1436 (1987)! andN,O-bis-(trimethylsilyl)acetamide (47.6 mL, 193 mmol) in drydichloroethane (700 mL) was heated at 80° C. for 60 min. Volatiles wereremoved in vacuo and the residue was evaporated with toluene twice. Thesilylated purine and mercuric cyanide (29.6 g, 117 mmol) in benzene (800mL) was heated at reflux for 60 min, then a solution of2-(phenylselenyl)-ethoxymethyl chloride (24 g, 94.5 mmol) in benzene(100 mL) was added dropwise. The mixture was refluxed for 4 hr and thenallowed to stir for 15 hr at 25° C. The reaction was diluted with CH₂Cl₂ (500 mL) and quenched with aqueous saturated bicarbonate (1 L). Theorganic phase was washed with 2N potassium iodide (200 mL), dried(MgSO₄) and the solvents were removed in vacuo. The residual oil waschromatographed on silica gel using CH₂ Cl₂ /5% MeOH as eluent toprovide the title compound as a slightly yellow powder: yield 22 g(39%).

Analysis: Calcd. for C₂₉ H₂₅ N₆ O₄ Se: C, 57.91, H, 4.36; N, 13.98.Found: C, 57.76; H, 4.46, N, 13.48.

¹ -NMR (300 MHz, CDCl₃): δ 2.459 (s, 3H), 2.951 (t, J=6.9 Hz, 2H), 3.714(t, J=6.9 Hz, 2H), 5.477 (s, 2H), 7.07-7.7 (m, 15H), 8.001 (s, 1H),8.171 (s, 1H).

¹³ C-NMR (75.45 MHz; CDCl₃): δ 25.133, 26.196, 69.192, 72.602, 120.363,126.970, 127.014, 129.174, 141.686, 143.734, 150.247, 152.487, 155.232,156.247, 156.297, 170.793.

Example 35 2-Acetamido-6-diphenylcarbamoyl-9-(vinyloxymethyl)purine (35)##STR58##

To a solution of 2-acetamido-6-diphenylcarbamoyl-9-2-(phenylselenyl)ethoxymethyl!purine (4.92 g, 8.16 mmol) in dioxane (80mL) was added 30% H₂ O₂ (4 mL, 35 mmol) and sodium bicarbonate (2.1 g,24.5 mmol). The mixture was heated at 60° C. for 20 min. The reactionwas then concentrated to about 10 mL, diluted with ethyl acetate (100mL), dried (MgSO₄) and the solvents were removed in vacuo. The residuewas dissolved in dioxane (40 mL), diisopropylethylamine (1.27 g, 10mmol) was added and the solution was heated at 80° C. for 30 min undernitrogen. The solvent was evaporated in vacuo and the residual oil waschromatographed on silica gel using CH₂ Cl₂ -ethyl acetate (1:1) aseluent to give the title compound as a yellowish powder: yield 2.3 g(65%).

Analysis: Calcd. for C₂₃ H₂₀ N₆ O₄.0.5H₂ O: C, 60.98; H, 4.67; N, 18.55.Found: C, 61.20; H; 4.76; N, 18.84.

¹ H-NMR (300 MHz, CDCl₃): δ 2.485 (s, 3H), 4.170 (dd, J=2.7, 6.6 Hz,1H), 44.473 (dd, J=2.7, 14.1 Hz, 1H), 6.395 (dd, J=6.6, 14.1 Hz, 1H).7.0-7.5 (m, 10H), 7.961 (s, 1H), 7,996 (s, 1H).

¹³ C-NMR (75.47 MHz, CDCl₃): δ 25.121, 70.572, 92.427, 126.272, 126.344,126.443, 126.496, 126.566, 126.644, 141.628, 143.226, 148.925, 152.552,170.505.

Example 36 2-Acetamido-6-diphenylcarbamoyloxy-9-(2-hydroxy-1-(dimethylphosphonomethoxy)ethoxymethyl!purine (36)##STR59##

To a suspension of2-acetamido-6-diphenylcarbamoyloxy-9-(vinyloxymethyl)purine (1.0 g, 2.25mmol) and dimethylphosphonomethanol (6 mL) in CH₂ Cl₂ (6 mL) was added80-85% m-chloroperbenzoic acid (611 mg, 3 mmol). After stirring for 18hr at 25° C., the clear solution was diluted with CH₂ Cl₂ (100 mL) andwashed with ice cold 1N NaOH (4 mL) and brine (20 mL). The organic phasewas washed again with brine (20 ML), dried (MgSO₄) and the solvent wasremoved in vacuo. The residual oil was chromatographed on silica gelusing using CH₂ Cl₂ /5% MeOH as eluent to give the title compound as acolorless oil: yield 360 mg (27%).

Analysis: Calcd. for C₂₆ H₂₉ N₆ O₉ P.0.5CH₂ Cl₂ : C, 49.22; H, 4.64; N,13.00. Found: C, 49.89; H, 4.47; N, 12.76.

¹ H-NMR (300 MHz, CDCl₃): δ 2.384 (s, 3H), 3.582 (dd, J=4.5, 12.5 Hz,1H), 3.722 (dd, J=4.5, 12.5 Hz, H), 3.768 (dd, J=2.9, 10.7 Hz, 6H),3.798 (dd, J=8.9, 4.0 Hz, 1H), 3.994 (dd, J=8.9, 14.0 Hz, 1H), 4.910,(t, J=4.9 Hz, 1H), 5.649 (d, J=10.8 Hz, 1H), 5.723 (d, J=10.8 Hz, 1H),7.0-7.4 (m, 10H), 8.032 (s, 1H), 8.662 (s, 1H).

Example 37 9- (2-Hydroxy-1-(methylphosphonomethoxyethoxymethyl!guanineammonium salt (37) ##STR60##

A solution of 2-acetamido-6-diphenylcarbamoyloxy-9-(2-hydroxy-1-(dimethylphosphonomethoxy)ethoxy)methyl!guanine (2.9 g, 4.8mmol) in methanol (300 mL) and 28% NH₄ OH (300 mL) was heated at 60° C.for 90 min The solution was concentrated in vacuo and the residual oilwas purified by C₁₈ reverse phase column chromatography using water aseluent under 8 psi pressure. The fractions having ultraviolet fractionswere checked with HPLC, combined and lyophilized to give the titlecompound as a white powder: yield 1.15 g (65%).

Analysis: Calcd. for C₁₀ H₁₉ N₆ O₇ P.H₂ O: C, 31.26; H, 5.51; N, 21.87.Found: C, 31.63; H, 5.43; N, 21.72.

¹ H-NMR (300 MHz, D₂ O): δ 3.549 (d, J=10.5 Hz, 3H), 3.571 (dd, J=4.8,13.2 Hz, 1H), 3.675 (dd, J=9.3, 13.2 Hz, 1H), 3.4-3.6 (m, 2H), 4.844 (t,J=3.9 Hz, 1H), 5.573 (d, J=11.4 Hz, 1H), 5.638 (d, J=11.4 Hz, 1H), 7.934(s, 1H).

UV_(max) (H₂ O): 252 nm (ε=13, 871).

Example 38 9- (2-Hydroxy-1-(phosphonomethoxy)ethoxy)methyl!guaninedisodium salt (38) ##STR61##

To a solution of 9-2-hydroxy-1-(methylphosphonomethoxy)ethoxy)methyl!guanine ammonium salt(780 mg, 2.0 mmol) in dry DMF (20 mL) was added at 5° C.bromotrimethysilyl (8 mL, 60 mmol) under nitrogen. After stirring for 3hr at 5° C., volatiles were removed in vacuo and the residue wasdissolved in aqueous saturated bicarbonate and re-evaporated in vacuo toa solid. Purification of this material by C₁₈ reverse phase columnchromatography using water as eluent under 8 psi pressure andlyophilization of combined fractions gave the title compound as a whitepowder: yield 520 mg (62%).

Analysis: Calcd. for C₉ H₁₂ N₅ O₇ PNa₂.2H₂ O: C, 26.04; H, 3.89; N,16.87; Found: C, 26.25; H, 4.05; N, 16.89.

UV_(max) (H₂ O): 252 nm (ε=15,150).

¹ H-NMR (300 MHz, D₂ O): δ 3.40-3.50 (m, 2H), 3.605 (dd, J=5.4, 11.6 Hz,1H), 3.698 (dd, J=9.0, 11.6 Hz, 1H), 4.877 (t, J=4.5 Hz, 1H), 5.665 (d,J=11.3 Hz, 1H), 5.725 (d, J=11.3 Hz, 1H), 7.999 (s, 1H).

¹³ C-NMR (75.47 MHz, D₂ O): δ 63.268, 65.832, 67.834, 71.636, 104.561,104.712, 117.980, 141.823, 153.521, 156.320, 161.129.

Example 39 1-(4-Methoxytetrahydro-2-fury1)thymine (3A) ##STR62##

To a suspension of 2.5 g (20 mmol) of dry, powdered thymine in 30 mL ofhexamethyldisilazane was added 50 mg of ammonium sulfate and 0.5 mL oftrimethylsilyl chloride. The mixture was heated at 140°-145° for 4 hr toobtain a clear solution. The excess hexamethyldisilazane was removed atreduced pressure, then the residual white oil was dissolved in xyleneand evaporated in high vacuum to give a colorless viscous oil. The crudesilylated thymine was dissolved in 40 mL of dichloroethane and cooled to-30° C., followed by 7.8g (60 mmol) of 2,5-dimethoxytetrahydrofuran. Tothis solution was added 2.3 mL of tin tetrachloride via a syringe over 2min, then stirred for 10 min under nitrogen. The mixture reaction waspoured into ice-cold aqueous NaHCO₃ (100 mL)-ethyl acetate (100 mL). Themilky solution was filtered through celite and the organic layer wasseparated and dried over MgSO₄. Evaporation of the dried solvents gave ayellow oil which was chromatographed on SiO₂ (CH₂ Cl₂ /MeOH) to give 4.3g (95%) of 3A as a colorless oil. This oil was a mixture of the twoisomers (cis/trans) in a ratio of 1:1 as seen by analytical HPLC and ¹H-NMR.

¹ H-NMR (CDCl₃) δ 1.4-2.2 (m, 7H), 3.40 and 3.42 (two s, 3H), 5.2 and5.25 (two bs, 1H), 6.20 and 6.41 (two q, 1H, J=3.5, 7.0 Hz, and 4.0, 7.2Hz), 7.02 and 7.40 (two s, 1H).

Example 40 1-(5-Diethylphosphonomethoxytetrahydro-2-furyl)thymine##STR63##

To a solution of 600 mg (2.65 mmol) of 3A (Example 39) in 15 mL ofmethylene chloride was added 0.6 mL of trimethylsilyl bromide and heatedat 40°-45° C. for 10 min under nitrogen. The reaction was evaporated invacuo to give 4A as a yellow oil which was dissolved in 20 mL ofmethylene chloride followed by 440 mg (2.60 mmol) ofdiethylphosphonomethyl alcohol. This solution was cooled to -10° C.followed by 0.6 mL of triethylamine and stirred for 15 min without thecooling bath. After dilution with 40 mL of ethyl acetate, the reactionwas washed with water and brine. Evaporation of the dried (MgSO₄)solvent gave a yellow oil which was chromatographed over SiO₂ (CH₂ Cl₂/MeOH) to give 180 mg (18.5%) of 5A as a white oil. This oil was amixture of the two isomers cis/trans in a ratio of 1:1, as seen byanalytical HPLC and ¹ H-NMR; ¹ H-NMR (CDCl₃) δ 1.25 (t, 6H, J=7.0 Hz),1.95 and 2.0 (two s, 3H), 3.8-4.0 (m, 2H), 4.0-4.2 (m, 4H), 5.2 and 5.3(two bs, 1H), 6.2 and 6.42 (q,q, 1H, J =3.5, 7.0 Hz and 4.0, 7.2 Hz),7.0 and 7.4 (two s, 1H).

Example 41 Testing and evaluation of compounds against herpes virus

A. Plaque Reduction Assay

Herpes simplex virus (HSV) strains were grown and titered at 37° C. invero cells (African Green Monkey Kidney cells) and used for virus workbefore the tenth passage.

Cells were grown and maintained in Earle's Minimum Essential Medium(EMEM), Gibco Laboratories, supplemented with 0.75% sodium bicarbonate,2 mM 1-glutamine, Pen-strep. and 5-10% fetal calf serum.

The titer of HSV strains is determined by a plaque titration method(Roizman and Roane, Virology, 115:75-79, 1961). Tissue culture 24-wellpetri dishes are seeded with cells and used for assays whenapproximately 75% monolayer. Volumes (0.1 mL) of logarithmic dilutionsof the virus strain are inoculated onto each of triplicate wells, andabsorbed for one hr with intermittent shaking. The inoculum thereafteris removed, and 1 mL of 5-10% EMEM containing 0.3% human immune serumglobulin is added. After a 48 hr incubation period at 37° C. in a 5% CO₂atmosphere, the overlay medium is removed and the cell sheets stainedwith Giemsa stain. The number of plaques is counted, the triplicate isaveraged, and the number of plaque-forming units per mL is calculated.

The compounds are tested for activity against the herpes simplex stainsusing a stock solution of each compound freshly prepared. Appropriatedilution of each compound are made in 10% EMEM before usage. Theantiviral efficacy of each compound is determined using the plaquereduction assay described above. Briefly, tissue culture 24-well plates,with approximately 50 plaque forming units of HSV per 0.1 mL, and thevirus absorbed for 1 hr, with intermittent shaking. After removal of theinoculum, 1 mL of 10% EMEM containing two-fold dilutions of theappropriate drug are added in triplicates. Triplicate wells/platereceives no drug and are used as a virus control. After a 48-hrincubation period, at 37° C. in a 5% CO₂ atmosphere, the overlay mediumis removed, the cells are stained as described above, and plaques arecounted. The counts of triplicate wells are averaged, and the number ofplaques in the presence of each drug dilution are calculated.

The antiviral potency of the drug is determined by ID₅₀, the drugconcentration necessary to reduce the number of plaques by 50% of thosein the virus control cultures.

The results are shown below in Table 1:

                  TABLE 1                                                         ______________________________________                                        Antiviral Test Results of Compound 8 (see Example 8)                          against HSV-1 and HSV-2                                                                      ID.sub.50 (μg/mL)                                           Compound         HSV-1   HSV-2                                                ______________________________________                                        ACV (Acyclovir)  0.5     0.5                                                  Compound 8       2.6     11                                                   ______________________________________                                    

Example 42 Comparison of Compound 8 and Acyclovir (ACV) In Vivo

Groups of ten mice were inoculated intraperitoneally with from 200 to600 PFU/0.2 mL of Herpes simplex virus-1 (HL-34 strain). Different dosesof test compound were administered to separate groups of animals on aBID basis for five consecutive days commencing three hr afterinoculation. Treatment was by an intraperitoneal route. The experimentwas terminated 21 days post inoculation and the number of survivals ineach group was counted. The mean survival time (MST, days) wascalculated.

The results are shown in Table 2. Compound 8 is equally as active asACV.

                  TABLE 2                                                         ______________________________________                                        Antiviral Effect of Compound 8 Against HSV-1 Systemic                         Infection in Mice                                                             Compound  Dose (mg/kg/d)  Route  Survival                                     ______________________________________                                        Compound 8                                                                              300             i.p.   10/10                                                  100             i.p.   9/10                                                   10              i.p.   3/10                                         ACV       200             i.p.   6/7                                                    100             i.p    7/10                                         ______________________________________                                    

Treatment was initiated 3 hr post-infection and was given BID for 5consecutive days.

Example 43 Testing and evaluating of compounds against MurineRetroviruses

The compounds were evaluated for antiviral activity against murineleukemia virus (MuLV) strains using the UV-XC plaque assay (Rowe, etal., Virology, 42:1136, 1970).

The MuLV strains were grown in fetal mouse cells (SC-1) and used forantiviral tests using the UV-XC plaque assay. Briefly, SC-1 cells aregrown as monolayers in 4-well tissue culture plates and inoculated withapproximately 50-100 plaque forming units of MuLV in 0.5 mL of 5% EMEMcontaining 20 μg/mL DEAE/Dextran. After 1 hr adsorption, the inoculum isremoved and 5 mL of 5% EMEM containing three-fold dilutions of theappropriate drug are added. Five days later, the cultures areUV-irradiated with an ultraviolet lamp and rat XC sarcoma cells areadded to the cultures. Three-four days after UV-irradiation, the cellcultures are stained with Giemsa stain and the plaques are enumerated.Antiviral activity is expressed in terms of the reduction in the meannumber of UX-XC plaques counted in the drug treated, virus-infectedcultures compared with mean number of plaques counted in untreated,virus-infected control cultures.

Example 44 In Vitro Evaluation Against HIV

The following HIV in vitro assay was used: The anti-HIV/LAV activity ismeasured in cultures of CEM-F cells. The CEM cells are infected withapproximately 30 TCID₅₀ (50% tissue culture infectious dose of HIV (LAVstrain). The cells are then incubated for 45 min at 37° C. The testcompounds in culture medium are added at various concentrations to theinfected cells and then incubated for a further 8 days. After 8 days theantiviral activity was evaluated in the culture media supernatant forp24 gag protein by an enzyme capture assay (ELISA). The antiviralactivity was expressed as the dose that inhibits 50% of the virusexpression (ID₅₀ in μg/mL) as detected by the assay described.

                  TABLE 3                                                         ______________________________________                                        Antiviral Test Results of Compound 25 (see Example 25)                        against Retroviruses                                                                         ID.sub.50 (μg/mL)                                           Compound         R-MuLV   HIV                                                 ______________________________________                                        AZT              0.05     0.1                                                 Compound 25      0.3      1.8                                                 ______________________________________                                    

Example 456-N-Pivaloyl-9-(2,3-dideoxy-3,4-dihydro-β-D-erythrofuranosyl)adenine##STR64##

To a solution of 9-(2,3-dideoxy-3,4-dihydro-β-D-erythrofuranosyl)adenine(2.0 g, 10 mmol) prepared according to the literature procedure: J.Zemlicka, R. Gasser, J. V. Freisler, J. P. Horwitz, J. Amer. Chem. Soc.,94, 3213 (1972)! in 1,2-dichloroethane (10 mL) was added pyridine (1mL), dimethylaminopyridine (170 mg) and pivaloyl chloride (1.5 g, 12mmol). The resulting solution was heated at 55°-60° C. for 6 hr undernitrogen. The mixture was then concentrated in vacuo, taken up in CH₂Cl₂ and washed with water, 20% H₃ PO₄ and brine, dried over MgSO₄, andevaporated in vacuo. The residual oil was chromatographed on silica gelusing CH₂ Cl₂ /3% MeOH as eluent to give the product (2.45 g, 85%) as awhite powder.

¹ H-NMR (CDCl₃) δ 1.24 (s, 9H), 2.29 (ddd, J=3.5, 5.0, 17.1 Hz, 1H),3.33 (dddd, J=2.4, 5.0, 9.4, 17.1 Hz, 1H), 5.24 (dd, J=2.4, 5.0 Hz, 1H),6.41 (dd, J=3.5, 9.4 Hz, 1H), 6.48 (dd, J=2.4, 5.0 Hz, 1H), 8.18 (s,1H), 8.73 (s, 1H).

Example 46 6-N-Pivaloyl-9-2,3-dideoxy-4-β-chloro-3-α-phenylselenyl)-β-D-erythrofuranosyl!adenine##STR65##

To a solution of the product of Example 45 (3.5 g, 12.2 mmol) in CH₂ Cl₂(40 mL) was added at -25° C. a solution of phenylselenyl chloride (2.7g, 14.0 mmol) in CH₂ Cl₂ (7 mL) over 5 min under nitrogen. Afterstirring for 30 min at -25° C., the solvent was removed in vacuo to givethe product as a yellow oil. This material was used promptly for thenext reaction:

¹ H-NMR (CDCl₃) δ 1.41 (s, 9H), 2.88 (m, 1H), 3.23 (m, 1H), 4.36 (d,J=6.3 Hz, 1H), 6.29 (s, 1H), 6.80 (dd, J=6.6, 8.4 Hz, 1H), 8.53 (s, 1H),8.77 (s, 1H).

Example 47 6-N-Pivaloyl-9-2,3-dideoxy-4-β-dimethylphosphonomethoxy-3-α-(phenylselenyl)-β-D-erythrofuranosyl!adenine##STR66##

To a solution of the product of Example 46 (approximately 12 mmol) anddimethylhydroxymethylphosphonate (16.8 g, 120 mmol) prepared accordingto the literature procedure: D. P. Philion and S. S. Andres, TetrahedronLett. 27, 1477 (1986)! in CH₂ Cl₂ (15 mL) was added at -25° C. asuspended solution of silver perchlorate (4.0 g, 20 mmol) in CH₂ Cl₂ (10mL) and dimethyl hydroxymethylphosphonate (5 mL) over 5 min undernitrogen. The mixture was allowed to warm to 0° C., stirred for 60 minand was then poured into CH₂ Cl₂ (100 mL)-aqueous bicarbonate (100mL)-brine (50 mL). The organic phase was separated after filtration,dried over MgSO₄ and evaporated. The residual oil was chromatographed onsilica gel using CH₂ Cl₂ /5% MeOH as eluent to give the product (3.2 g,45%) as a colorless oil:

¹ H-NMR (CDCl₃) δ 1.25 (s, 9H), 2.61 (ddd, J=2.7, 6.6, 14.4 Hz, 1H),2.96 (ddd, J=6.6, 7.5, 14.4 Hz, 1H), 3.68 (d, J=11 Hz, 6H), 3.7-4.0 (m,3H), 5.24 (s, 1H), 8.27 (s, 1H), 8.67 (s, 1H).

Example 48 6-N-Pivaloyl-9-2,3-dideoxy-2,3-dihydro-4-β-(dimethylphosphono)methoxy-β-D-erythrofuranosyl!adenine##STR67##

To a solution of the product of Example 47 (3.3 g, 5.6 mmol) in dioxane(30 mL) was added a solution of sodium periodate (6.3 g, 30 mmol) inwater (30 mL) and the resulting solution was stirred at 23° C. for 4 hr.CH₂ Cl₂ (200 mL) was added and the mixture was filtered through Celite.The organic phase was washed with water, brine, dried over MgSO₄ andevaporated in vacuo. The residual oil was chromatographed on silica gelusing CH₂ Cl₂ /5% MeOH as eluent to give the product (1.4 g, 57%) as acolorless oil:

¹ H-NMR (CDCl₃) δ 1.31 (s, 6H), 3.64 (d, J=10.8 Hz, 3H), 3.71 (d, J=10.8Hz, 3H), 3.84 (dd, J=8.7, 9.9 Hz, 1H), 5.87 (s, 1H), 6.27 (d, J=6.0 Hz,1H), 6.34 (dd, J=1.5, 6.0 Hz, 1H), 7.00 (d, J=1.5 Hz, 1H), 8.04 (s, 1H),8.66 (s, 1H);

¹³ C-NMR (CDCl₃) δ 27.524, 40.607, 53.318 (d, J=6.2 Hz), 61.598 (d,J=165 Hz), 86.247, 109.202, 123.406, 130.657, 132.679, 141.966, 150.205,152.056, 176.547.

Example 49 9-2,3-Dideoxy-2,3-didehydro-4-β-(methylphosphono)methoxy-β-D-erythrofuranosyl!adenineammonium salt ##STR68##

A solution of the product of Example 48 (330 mg, 0.78 mmol) and sodiummethoxide (250 mg, 4.6 mmol) in methanol (10 mL) was stirred at 23° C.for 18 hr. The reaction was carefully neutralized to pH 5.0 by dropwiseaddition of 2N HCl in an ice bath. The pH of the solution was readjustedto 8.0 by concentrated NH₄ OH and volatiles were removed in vacuo. Thesolid residue was purified by C₁₈ reverse-phase column using water aseluent under 8 psi pressure to give the product (141 mg, 49%) as a whiteamorphous powder:

¹ H-NMR (D₂ O) δ 3.34 (d, J=10.5 Hz, 3H), 3.65 (dd, J=9.2, 13.2 Hz, 1H),3.80 (dd, J=9.2, 13.2 Hz, 1H), 5.99 (s, 1H), 6.57 (s, 2H), 6.83 (s, 1H),8.11 (s, 1H), 8.14 (s, 1H);

¹³ C-NMR (D₂ O) 58.542 (d, J=3.0 Hz), 68.483 (d, J=150 Hz), 92.797,116.319, 125.121, 136.147, 139.719, 147.131, 155.275, 159.781, 162.359;

UV_(max) (H₂ O) 260 nm (ε 12,964).

Example 50 9-2,3-Dideoxy-2,3-dihydro-4-β-phosphonomethoxy-β-D-erythrofuranosyl!adenineammonium salt ##STR69##

A solution of the product of Example 49 (310 mg, 0.9 mmol) andtrimethylsilylbromide (1.0 mL) in DMF (4 mL) was stirred at 0° C. for 3hr under nitrogen. Volatiles were removed in vacuo and the residue wasdissolved in concentrated NH₄ OH (2 mL). Water was evaporated in vacuoand the residual solid was purified by C₁₈ reverse-phase column usingwater as eluent under 8 psi pressure to give the product (128 mg, 43%)as a white amorphous powder.

UV_(max) (H₂ O) 260 nm (ε 14,982);

¹ H-NMR (D₂ O) δ 3.59 (dd, J=9.3, 22.2 Hz, 1H), 3.69 (dd, J=9.3, 22.2Hz, 1H), 5.99 (s, 1H), 6.46 (d, J=6.0 Hz, 1H), 6.50 (d, J=6.0 Hz, 1H),6.83 (s, 1H), 7.87 (s, 1H), 8.13 (s, 1H);

¹³ C-NMR (D₂ O) δ 70.756 (d, J=150 Hz), 93.065, 116.510, 122.434,136.579, 139.835, 147.763, 155.424, 158.990, 161.809.

Anal. Calcd. for C₁₀ H₁₅ N₆ O₅ P.3H₂ O: C, 31.25; H, 5.46; N, 21.87.Found: C, 31.32; H, 5.85; N, 22.15.

This compound was evaluated for anti-retroviral activity by the methodsdescribed in Examples 43 and 44. The results are shown in Table IV. AZTcontrols were run simultaneously to confirm the validity of the test.

                  TABLE IV                                                        ______________________________________                                        Virus       Cell-line  Cell-tox.                                                                              ID.sub.50                                     ______________________________________                                        HIV         CEM        >100 μm                                                                              45 μm                                     HIV         MT-4       >500 μm                                                                             1.5 μm                                     R-MuLV      SC-1       >100 μm                                                                             0.01 μm                                    ______________________________________                                    

Example 51 6-N-Pivaloyl-9-2,3-dideoxy-4-β-(dimethylphosphonomethoxy-3-α-iodo-β-D-erythrofuranosyl!adenine##STR70##

To a solution of the product of Example 45 (3.5 g, 12.2 mmol) anddimethyl hydroxymethylphosphonate (16.8 g, 120 mmol) in CH₂ Cl₂ (40 mL)was added portionwise at 0° C. N-iodosuccinimide (2.75 g, 12.2 mmol) andthe mixture was stirred for 2 hr at 0° C. The reaction was diluted withCH₂ Cl₂ (50 mL), washed with water, brine, and dried over MgSO₄. Theresidual oil was chromatographed on silica gel using CH₂ Cl₂ /3% MeOH aseluent to give the product (4.9 g, 72%) as a slightly yellow oil.

¹ H-NMR (CDCl₃) δ 1.36 (s, 9H), 2.89 (dd, J=6.3, 9.7 Hz, 1H), 3.20 (dd,J-6.3, 10.3 Hz, 1H), 3.7-3.9 (m, 8H), 4.49 (d, J=5.4 Hz, 1H), 5.50 (s,1H), 6.86 (t, J=7.2 Hz, 1H), 8.29 (s, 1H), 8.50 (bs, 1H), 8.74 (s, 1H).

Example 52 6-N-Pivaloyl-9-2,3-dideoxy-2-3-dihydro-4-β-(dimethylphosphono)methoxy-β-D-erythrofuranosyl!adenine##STR71##

A solution of the product of Example 51 (1.7 g, 3.0 mmol) and1,8-diazabicyclo 5.4.0!undec-7-ene (912 mg, 6.0 mmol) in CHCl₃ (20 mL)was heated at 65° C. for hr. The reaction was washed with ice-cold 20%H₃ PO₄, brine, dried over MgSO₄ and evaporated in vacuo. The residualoil was purified on silica gel using CH₂ Cl₂ /3% MeOH as eluent to givethe product (1.2 g, 90%) as a colorless oil. This material was identicalwith the product of Example 48.

Example 53 1-2,3-Dideoxy-4-β-(phosphonomethoxy)-β-D-erythrofuranosyl!thymine disodiumsalt ##STR72##

A mixture of the product of Example 25 (200 mg, 0.57 mmol) and 10%palladium on active carbon (180 mg) in water (20 mL) was hydrogenatedfor 30 min under 30 psi H₂ pressure in the Parr hydrogenator. Thecatalyst was filtered through Celite with the aid of a water wash. Waterwas removed by lyophilization to give the desired product (205 mg, 100%)as a white amorphous powder:

UV_(max) (H₂ O) 268 nm (ε 8844);

¹ H-NMR (D₂ O) δ 1.86 (s, 3H), 2.0-2.4 (m, 4H), 3.41 (dd, J=8.1, 12.9Hz, 1H), 3.62 (dd, J=8.1, 12.9 Hz, 1H), 5.32 (t, J=2.7 Hz, 1H), 6.24 (t,J=7.0 Hz, 1H), 7.60 (s, 1H);

¹³ C-NMR (D₂ O) δ 18.49, 35.384, 38.041, 72.628, (d, J=150 Hz), 93.249,113.423, 118.884, 159.494, 174.169,

Anal. Calcd. for C₁₀ H₁₃ N₂ O₇ PNa₂.11/2 H₂ O: C, 31.83; H, 4.24; N,7.42. Found: C, 31.62; H, 3.95; N, 7.28

Example 54 6-N-Pivaloyl-9-4-β-(dimethylphosphono)methoxy-β-D-erythofuranosyl!adenine ##STR73##

To a solution of phenylboric acid (860 mg, 7.0 mmol) and4-methylmorpholine N-oxide (900 mg, 7.5 mmol) in CH₂ Cl₂ (20 mL) wasadded, at 23° C., osmium tetroxide (25 mg) followed by the product ofExample 52 (2.75 g, 6.4 mmol) in CH₂ Cl₂ (10 mL). The mixture wasstirred for 2 hr and 10% aqueous sodium bisulfite (4 mL) was added.After stirring for 1 hr, the CH₂ Cl₂ was separated, washed with brineand dried over MgSO₄. Evaporation of solvent gave a white oil which wasdissolved in acetone (15 mL) and 1,3-dipropanol (760 mg, 10 mmol). Allvolatiles were removed in vacuo and the resulting oil waschromatographed over silica gel using CH₂ Cl₂ /7% MeOH as eluent to givethe above-named compound (2.3 g, 76%) as a white foam:

¹ H-NMR (CDCl₃) δ 1.28 (s, 9H), 3.72 (d, J=10.5 Hz, 6H), 3.73 (dd,J=10.6, 13.5 Hz, 1H), 3.95 (d, J=10.6, 13.5 Hz, 1H) 4.91 (dd,J=4.5, 6.3Hz, 1H), 4.33 (d, J=4.5 Hz, 1H), 5.09 (s, 1H), 6.38 (d, J=6.3 Hz, 1H),8.35 (s, 1H), 8.49 (s, 1H), 8.83 (bs, 1H).

Example 55 9-4-β-(Methoxyhydroxyphosphinyl)methoxy-β-D-erythrofuranosyl!adenineammonium salt ##STR74##

A solution of the product of Example 54 (2.2 g, 4.8 mmol) and sodiummethoxide (1.49, 26 mmol) in methanol (50 mL) was stirred at 23° C. for7 hr under nitrogen. Volatiles were removed in vacuo and the residualoil was dissolved in water (20 mL). The aqueous solution was heated at35° C. for 10 hr. The reaction was carefully neutralized to pH 5.0 bydropwise addition of 2N HCl in an ice bath. The solution was thenreadjusted to pH 8.0 with concentrated NH₄ OH and volatiles were removedin vacuo. The solid residue was purified by C₁₈ reverse-phase columnusing water/5% CH₃ Cl as eluent under 8 psi pressure to give the product(1.3 g, 75%):

UV_(max) (H₂ O) 260 nm (ε 10,019);

¹ H-NMR (D₂ O) δ 3.56 (d, J=10.5 Hz, 3H), 3.61 (dd, J=10, 12.9 Hz, 1H),3.83 (dd, J=10, 12.9 Hz, 1H), 4.38 (d, J=11.0 Hz, 1H), 5.0 (dd, J=6.2,11.0 Hz, 1H), 5.19 (s, 1H);

¹³ C-NMR (D₂ O) δ 53.897 (d, J=6.0 Hz), 64.192 (d, J=150 Hz), 75.589,75,909, 111.096, 141.824, 151.079, 154.785, 157.354.

Example 56 9- 4-β-(phosphonomethoxy)methoxy-β-D-erythrofuranosyl!adenineammonium salt ##STR75##

A solution of the product of Example 55 (1.5 g, 4.1 mmol) andtrimethylsilyl bromide (7 mL) in DMF (30 mL) was stirred at 23° C. for 6hr under nitrogen. The volatiles were removed in vacuo and the residuewas dissolved in concentrated NH₄ OH (3 mL). Water was evaporated invacuo and the residual solid was purified by C₁₈ reverse-phase columnusing water as eluent to give 12 (600 mg, 40%) as a white amorphouspowder:

UV_(max) (H₂ O) 262 nm (ε 12,640);

¹ H-NMR (D₂ O) δ 3.56 (dd, J=10.0, 12.9 Hz, 1H), 3.79 (dd, J=10.0, 12.9Hz, 1H), 4.31 (d, J=11.0 Hz, 1H), 4.92 (dd, J=6.0, 11.0 Hz, 1H), 5.17(s, 1H), 6.08 (d, J=10 Hz, 1H), 8.24 (s, 1H), 8.25 (s, 1H).

¹³ C-NMR (D₂ O) δ 66.296 (d, J=157 Hz), 75.881, 76.967, 88.982, 111.148,119.927, 142.208, 150.689, 153,560, 156.330.

Anal. Calcd. for C₁₀ H₁₇ N₆ O₇ P.H₂ O: C, 30.05; H, 5.26, N. 21.03.Found: C, 30.09; H, 5.06; N, 20.38

EXAMPLE 57 (2R,5R)-1-2,5-Dihydro-5-(dimethoxyphosphinyl)methoxy-2-furanyl!uracil ##STR76## A.(2R,4S,5S)-1-Tetrahydro-4-iodo-5-(dimethoxyphosphinyl)methoxy)methoxy-2-furanyl!uracil##STR77##

To a solution of the glycal A (1.0 g, 5.5 mmol) prepared according tothe literature procedure: Zemlicka, J.; Gasser, R.; Friesler, J. V.;Horwitz, J. P., J. Am. Chem. Soc. (1972) 94, 3213! and dimethyl(hydroxymethyl)phosphonate (7.8 g, 55 mmol) in CH₂ Cl₂ (10 mL) at -780°C. was added a solution of iodine bromide (2.3 g, 11 mmol) in CH₂ Cl₂(10 mL over a period of 15 min. After being stirred at -78° C. for 90min, the mixture was diluted with CH₂ Cl₂ (50 mL) and aqueous NaHCO₃.The organic phase was washed with aqueous sodium bisulfite, dried overMgSO₄, and evaporated in vacuo. The residual oil was chromatographed onsilica gel using CH₂ Cl₂ /5% MeOH as eluent to give the noted product B(1.3 g, 50%) as a colorless oil:

¹ H-NMR (CDCl₃) δ 2.5-2.7 (m, 2H), 3.7-4.05 (m, 8H), 4.29 (d, J=4.9 Hz,1H), 5.33 (s, 1H), 5.77 (d, J=8.2 Hz, 1H), 6.73 (t, J=7.1 Hz, 1H), 7.56(d, J=8.2 Hz, 1H), 9.83 (br s, 1H);

¹³ C-NMR (CDCl₃) δ 20.21, 40.31, 53.68, 60.92 (d, J=172 Hz), 86.57,104.56, 112.25 (d, J=13 Hz), 140.6, 151.28, 163.95.

B. To a solution of product B from part A (1.2 g, 2.7 mmol) in MeOH (5mL) at 0° C. was added 25% sodium methoxide in MeOH (3 mL). After beingstirred at 25° C. for 16 hr, the reaction mixture was neutralized to pH8.0 by dropwise addition of 2N HCl in an ice bath. Volatiles wereremoved in vacuo to dryness and the residue was chromatographed onsilica gel using CH₂ Cl₂ /7% MeOH as eluent to give the final product(500 mg, 62%) as a colorless oil:

¹ H-NMR (CDCl₃) δ 3.72 (d, J=6 Hz, 3H), 3.75 (d, J=5 Hz, 3H), 3.88 (dd,J=8.7, 13.8 Hz, 1H), 4.05 (dd, J=9.9, 13.8 Hz, 1H), 5.68 (d, J=8.1 Hz,1H), 5.73 (s, 1H), 6.06 (d, J=5.4 Hz, 1H), 6.26 (d, J=5.4 Hz, 1H), 6.93(s, 1H), 7.34 (d, J=8.1 Hz, 1H).

Anal. Calcd. for C₁₁ H₁₅ N₂ O₇ P: C, 41.51; H, 4.72; N, 8.81. Found: C,41.91; H, 5.05; N, 8.42.

Example 58 (2R,5R)-1-2,5-Dihydro-5-(dimethoxyphosphinyl)methoxy-2-furanyl!-5-chlorouracil##STR78##

To a solution of the product of Example 57 (400 mg, 1.3 mmol) inpyridine (15 mL) was added N-chlorosuccinimide (200 mg, 1.5 mmol) andthe solution was heated at 90°-95° C. for 30 min under nitrogen. Allvolatiles were removed in vacuo and the oily residue was chromatographedon silica gel using CH₂ Cl₂ /3% MeOH as eluent to give the product (390mg, 87%) as a colorless oil:

¹ H-NMR (CDCl₃) δ 3.73 (d, J=6.9 Hz, 3H), 3.78 (d, J=6.9 Hz, 3H), 3.93(dd, J=7.5, 13.8 Hz, 3H), 3.78 (d, J=6.9 Hz, 3H), 3.93 (dd, J=7.5, 13.8Hz, 1H), 4.09 (dd, J=10.2, 13.8 Hz, 1H), 5.73 (s, 1H), 6.09 (d, J=6 Hz,1H), 6.28 (d, J=6 Hz, 1H), 6.89 (s, 1H), 7.49 (s, 1H), 9.35 (br s, 1H).

Anal Calcd. for C₁₁ H₁₄ N₂ O₇ ClP: C, 37.45; H, 3.97; N, 7.94. Found: C,37.15; H, 4.28; N, 7.59.

Example 59 (2R,5R)-1-2,5-Dihydro-5-(phosphonomethoxy)-2-furanyl!-5-chlorouracil ##STR79##

To a solution of the product of Example 58 (380 mg, 1.1 mmol) in DMF (3mL) at 0° C. was added freshly distilled bromotrimethylsilane (2 mL).After the mixture was stirred at 25° C. for 2 hr, the volatiles wereremoved in vacuo and the residue was dissolved in concentrated NH₄ OH (3mL) and cooled in the ice bath. The white precipitate was collected byfiltration and washed with water, and air dried to give the product (145mg, 43%) as a white powder: m.p. 105°-106° C.; UV_(max) (EtOH) 276 nm (ε8052);

¹ H-NMR (DMSO-d₆) δ 3.68 (dd, J=3.9, 13 Hz, 1H), 3.71 (dd, J=4.8, 13 Hz,1H), 5.81 (s, 1H), 6.26 (d, J=6 Hz, 1H), 6.41 (d, J=6 Hz, 1H), 6.71 (s,1H), 7.48 (s, 1H);

¹³ C-NMR (DMSO-d₆) δ 63.42 (d, J=162 Hz), 87.78, 108.21 (d, J=15 Hz),108.36, 130.41, 132.28, 136.97, 149.63, 158.99.

Anal. Calcd. for C₉ H₁₀ N₂ O₇ ClP.H₂ O: C, 31.55; H, 3.53; N, 8.12: Cl,10.35. Found: C, 31.22; H, 3.52: N, 7.97; Cl, 9.81.

Example 60 (2R,4S,5R)-1- tetrahydro-4-(phenylselenyl)-5-(dimethoxyphosphinyl)methoxy!-2-furanyl!-5-iodouracil ##STR80## A.2'-Deoxy-5-iodouridine-5'-carboxylic acid

The platinum-catalyzed oxidation of 2'-deoxy-5-iodouridine followed theliterature procedure Moss, G. P.; Reese, C. B.; Schofield, K.; Shapiro,R.; Todd, A. R., J. Chem. Soc. (1963), 1149! to give the product in 35%yield: m.p.>200° C. (dec.);

NMR (D₂ O) δ 2.2-2.4 (m, 2H), 4.57 (d, J=2.1 Hz, 1H), 6.36 (dd, J=6.3,8.1 Hz, 1H), 8.68 (s, 1H), one proton at the D₂ O (H₂ O) region(4.7-4.9).

Anal. Calcd. for C₉ H₉ N₂ O₆ I.H₂ O: C, 28.00; H, 2.87; N, 7.26. Found:C, 27.93; H, 2.74; N, 6.98.

B. A solution of the product of Part A (800 mg, 2.2 mmol) anddimethylformamide dineopentylacetal (4 mL) in DMF (30 mL) was heated for6 hr at 110° C. under N₂. After cooling, the reaction mixture wasevaporated in vacuo and the resulting residual oil was chromatographedon silica gel using CH₂ Cl₂ /5% MeOH as eluent to give the product (501mg, 79%) as a white crystal: m.p. 182° C.;

NMR (CDCl₃) δ 2.4-2.6 (m, 1H), 3.1-3.3 (m, 1H), 5.13 (dd, J=2.4,5.1 Hz,1H), 6.45 (dd, J=2.4,4.8 Hz, 1H), 6.57 (dd, J=3.9,6.5 Hz, 1H), 7.57 (s,1H), 8.31 (br s, 1H).

Anal. Calcd. for C₈ H₇ N₂ O₃ I: C, 31.40; H, 2.31; N, 9.16. Found: C,31.61; H, 2.31; N, 8.98.

C. To a solution of the glycal prepared in Part B (1.8 g, 6.1 mmol) anddimethyl(hydroxymethyl)phosphonate (8.3 g, 59 mmol) in1,2-dichloroethane (20 mL) was added N-(phenylseleno)phthalimide (3.7 g,12.2 mmol) and the solution was heated at 80° C. for 2 hr. Aftercooling, the reaction was diluted with CH₂ Cl₂ (100 mL) and washed withwater (10 mL×4) and brine, dried over MgSO₄, and concentrated in vacuo.The residual oil was chromatographed over silica gel using CH₂ Cl₂ /5%MeOH as eluent to give the product (2.2 g, 60%) as a colorless oil:

¹ H-NMR (CDCl₃) δ 2.4-25 (m, 2H), 3.75 (d, J=10.8 Hz, 6H), 3.78 (m, 1H),3.88 (dd, J=4.2, 14.1 Hz, 1H), 3.94 (dd, J=8.5, 14.1 Hz, 1H), 5.17 (s,1H), 6.37 (t, J=6.6 Hz, 1H). 7.3-7.6 (m, 5H), 7.86 (s, 1H), 9.35 (s,1H).

Example 61 (2R,5R)-1- 2,5-Dihydro-5-dimethoxyphosphinyl)methoxy!-2-furanyl!-5-iodouracil ##STR81##

A solution of the product of Example 60 (440 mg, 0.73 mmol), NaHCO₃ (250mg) and 30% H₂ O₂ (0.3 mL) in 1,4-dioxane-water (2:1, 8 mL) was stirredat 25° C. for 4 hr. All volatiles were removed in vacuo and the residuewas extracted with CH₂ Cl₂ (30 mL). The CH₂ Cl₂ was dried (MgSO₄) andevaporated in vacuo. The residual oil was chromatographed on silica gelusing CH₂ Cl₂ /5% MeOH as eluent to give the product (233 mg, 70%) as awhite crystal: m.p. 192° C. (dec.);

¹ H-NMR (CDCl₃) δ 3.58 (d, J=10.8 Hz, 1H), 3.62 (d, J=10.8 Hz, 1H), 3.83(dd, J=9.6, 13.8 Hz, 1H), 3.983 (dd, J=9.3, 13.8 Hz, 1H), 5.58 (s, 1H),6.01 (d, J=7.2 Hz, 1H), 6.19 (d, J=7.2 Hz, 1H), 6.24 (s, 1H), 7.50 (s,1H).

Anal. Calcd. for C₁₁ H₁₄ N₂ O₇ PI: C, 29.75; H, 3.18; N, 6.31. Found: C,29.79; H, 3.15; N, 5.99.

Example 62 (2R,5R)-1-2,5-Dihydro-5-(phosphonomethoxy)-2-furanyl!-5-ioduracil monoammoniumsalt ##STR82##

To a solution of the product of Example 61 (150 mg, 0.34 mmol) in dryDMF (4 mL) was added freshly distilled bromotrimethylsilane (2 mL).After the mixture was stirred at 0° C. for 2 hr, the volatiles wereremoved in vacuo and the residue was dissolved in concentrated NH₄ OH(10 mL) and then evaporated in vacuo to dryness. The residual solid waspurified by C₁₈ reverse-phase column chromatography under 8 psi ofpressure using water as eluent to give the product (74 mg, 50%) as anamorphous powder: UV_(max) (H₂ O) 286 nm (ε 8323); ¹³ C-NMR (D₂ O) δ67.38 (d, J=157 Hz), 90.90, 111.86 (d, J=11 Hz), 131.95, 135.59, 149.09,154.33, 161.42, 165.78.

Anal. Calcd. for C₉ H₁₃ N₃ O₇ PI.H₂ O: C, 24.16; H, 3.32; N, 9.31.Found: C, 24.50; H, 2.99, N, 9.73.

Example 63 (2'R,5'R)-9-2,5-Dihydro-5-(dimethoxyphosphinyl)methoxy-2-furanyl!adenine ##STR83##

To a solution of the product of Example 48 or 52 (5.7 g, 13.3 mmol) inMeOH (50 mL) at 23° C. was added sodium methoxide (3.0 g, 65 mmol).After being stirred at 23° C. for 5 hr, the solution was cooled to 0° C.and the pH was adjusted to 7-8 by addition of 6N HCl. All volatiles wereremoved in vacuo and the residue was dissolved in CH₂ Cl₂ /3% MeOH anddried over MgSO₄ and then evaporated in vacuo to dryness. The residualoil was chromatographed on silica gel using CH₂ Cl₂ /5% MeOH as eluentto give the product (2.8 g, 80%) as a white solid: m.p. 146°-149° C.;

¹ H-NMR (CDCl₃) δ 3.70 (d, J=10.8 Hz, 3H), 3.76 (d, J=10.78 Hz, 3H),3.86 (dd, J=8.7, 13.8 Hz), 4.03 (dd, J=9.9, 13.8 Hz, 1H), 5.85 (s, 1H),5.91 (br s, 1H), 6.29 (d, J=5.7 Hz, 1H), 6.39 (d, J=5.7 Hz, 1H), 6.99(s, 1H), 7.94 (s, 1H), 8.36 (s, 1H).

¹³ C-NMR (CDCl₃) δ 61.49 (d, J=170 Hz), 86.29, 108.99, 109.16, 119.93,131.04, 132.33, 139.56, 150.23, 154.07, 156.51.

Example 64 (2'R,5'R)-9-2,5-Dihydro-5-(dimethoxyphosphinyl)methoxy-2-furanyl!adenine 1-N-oxide##STR84##

To a solution of the product of Example 63 (1.62 g, 4.75 mmol) in CH₂Cl₂ (50 mL) was added 80-85% 3-chloroperoxybenzoic acid (1.0 g, ca. 0.5mmol) and the resulting yellow solution was stirred at 23° C. for 3 hr.After evaporation of CH₂ Cl₂, the residue was triturated withether/hexane (1:9, 100 mL) to obtain 1.68 g (98%) of the product as anamorphous powder:

UV_(max) (EtOH) 236 nm (ε 3976);

¹ H-NMR (DMSO-d₆) δ 3.58 (d, J=10.6 Hz, 3H), 3.62 (d, J=10.6 Hz, 3H),3.95 (d, J=9.5 Hz, 2H), 4.1 (br s, 2H), 5.95 (s, 1H) 6.48 (d, J=5.9 Hz,1H), 6.61 (d, J=5.9 Hz, 1H), 6.84 (s, 1H), 8.11 (s, 1H), 8.68 (s, 1H);

¹³ C-NMR (DMSO-d₆) 53.45 (d, J=6.5 Hz), 61.68 (d, J=171 Hz) , 86.34,109.25, 119.30, 130.92, 132.50, 142.26, 142.95, 145.21, 149.41.

Anal. Calcd. for C₁₂ H₁₅ N₅ O₆ P.H₂ O: C, 38.29; H, 3.9: N, 18.61.Found: C, 38.43; H, 4.04; N, 18.89.

Example 65 (2'R,5'R)-2,6-Diamino-9-2,5-dihydro-5-(dimethoxyphosphinyl)methoxy-2-furanyl!purine ##STR85## A.2-Imino-7-(2R,5R)-2,5-dihydro-5-(dimethoxyphosphinyl)methoxy-2-furanyl!-1,2,4-oxadiazolo-(3,2-i)purine!hydrobromide ##STR86##

To a solution of the product of Example 64 (1.62 g, 4.53 mmol) in MeOHwas added cyanogen bromide (530 mg, 5.0 mmol). After 2 hr at 23° C., theMeOH was evaporated in vacuo to give a colorless oil, which wastriturated with ether/hexane (1:9) to give the product (1.89 g, 90%) asan amorphous powder: UV_(max) (EtOH) 222 nm (ε 15325), 282 nm (ε 11682);

¹ H-NMR (CH₃ OD) δ 3.47 (d, J=10.8 Hz, 3H), 3.52 (d, J=10.8 Hz, 3H),3.82 (d, J=9.6 Hz, 2H), 5.75 (s, 1H) 6.35 (s, 2H), 6.93 (s, 1H), 8.34(s, 1H), 9.54 (s, 1H).

Anal. Calcd. for C₁₃ H₁₆ N₆ O₆ PBr: C, 33.69; H, 3.45; N, 18.14. Found:C, 33.29; H, 3.64: N, 17.90.

B. (2'R,5'R)-2-Amino-6-methoxy-9-2,5-dihydro-5-(dimethoxyphosphinyl)methoxy-2-furanyl!adenine ##STR87##

To a solution of the product of part A (3.2 g, 6.9 mmol) in DMF (50 mL)at 23° C. was added TEA (1.5 mL) followed by iodomethane (2 mL) followedby iodomethane (2 mL). After being stirred for 5 hr, all volatiles wereremoved in vacuo. The resulting oil was chromatographed on silica gelusing CH₂ Cl₂ /7% MeOH as eluent to give the intermediate product (2.1g, 81%) as a slightly yellow oil:

¹ H-NMR (CD₃ OD) δ 3.58 (d, J=10.7 Hz, 3H), 3.62 (d, J=10.7 Hz, 3H),3.85 (dd, J=9.2, 13.9 Hz, 1H), 3.88 (dd, J=9.2, 13.9 Hz, 1H), 3.88 (dd,J=9.2, 13.9 Hz, 1H), 4.07 (s, 3H), 5.81 (s, 1H), 6.38 (d, J=4.8 Hz, 1H),6.42 (d, J=4.8 Hz, 1H), 6.80 (s, 1H), 7.95 (s, 1H), 8.59 (s, (1H);

IR Film (cm⁻¹) 2180, 1630.

A solution of the intermediate (1.3 g, 3.3 mmol) in 0.05N NaOH (80 mL)was stirred at 23° C. for 45 min The pH of the solution was adjusted to7.5 with 1N HCl and the resulting solution was heated at 70°-75° C. for2 hr. After cooling, all volatiles were removed in vacuo. The cruderesidue was chromatographed on silica gel using CH₂ Cl₂ /10% MeOH aseluent to give the product (70 mg, 56%) as a colorless oil: UV_(max)(EtOH) 214 nm (ε 13471), 280 nm (ε 11927);

¹ H-NMR (CD₃ OD) δ 3.60 (d, J=11.1 Hz, 3H), 3.65 (d, J=11.1 Hz, 3H),3.79 (dd, J=9.2, 13.5 Hz, 1H), 3.94 (dd, J=11.0, 13.5 Hz, 1H), 5.72 (s,1H), 6.23 (s, 2H) 6.63 (s, 1H) 7.41 (s, 1H).

Anal. Calcd. for C₁₃ H₁₉ N₆ O₆ P: C, 40.41; H, 4.92; N, 21.76. Found: C,39.98; H, 4.86; N, 21.69.

C. To a solution of the product of part B (1.5 g, 3.8 mmol) intetrahydrofuran-water (9:1, 150 mL) at 23° C. was added 2.1 g of Al--Hgstrips (5 mm×40 mm, prepared from aluminum foil and 2% HgCl₂). Afterbeing stirred at 23° C. for 30 min, the mixture was heated at 70° C. for60 min. The mixture was filtered through a pad of Celite and washed withtetrahydrofuran. The combined solvents were removed in vacuo. Theresidual oil was chromatographed on silica gel using CH₂ Cl₂ /10% MeOHas eluent to give the final product (540 mg, 40%) as a colorless oil:

¹ H-NMR (CD₃ OD) δ 3.43 (d, J=10.5 Hz, 3H), 3.49 (d, J=10.8 Hz, 3H),3.73 (dd, J=10.2, 12.3 Hz, 1H), 3.83 (dd, J=10.2, 12.3 Hz, 1H), 5.63 (s,1H) 6.19 (d, J=6 Hz, 1H), 6.21 (d, J=6 Hz, 1H), 6.53 (s, 1H), 7.45 (s,1H):

¹³ C-NMR (CD₃ OD) δ 53.87 (d, J=25 Hz), 60.93 (d, J=163 Hz), 87.14,110.28, 114.10, 132.85, 133.20, 136.87, 152.59, 157.63, 162.09.

Anal. Calcd. for C₁₂ H₁₇ N₆ O₅ P: C, 40.49; H, 4.82; N, 23.59. Found: C,40.07; H, 4.63; N, 23.86.

Example 66(2'R,5'R)-2,6-Diamino-9-(2,5-dihydro-5-phosphonomethoxy-2-furanyl)purine##STR88##

To a solution of the product of Example 65, (380 mg, 1.07 mmol) in DMF(4 mL) at 0° C. was added 2,6-lutidine (400 mg, 3.7 mmol) and freshlydistilled bromotrimethylsilane (2 mL). After being stirred at 23° C. for18 hr, all volatiles were removed in vacuo and the pH was adjusted to11.0 by addition of ice cooled 10% NH₄ OH. After evaporation of water,the residue was purified by C₁₈ reverse-phase column chromatographyusing water as eluent under 8 psi pressure to give the product (275 mg,55%) as a white powder: m.p. 146°-152° C.; UV_(max) (H₂ O) 256 nm (ε8406), 280 nm (ε 9044 );

¹ H-NMR (D₂ O) δ 3.34 (dd, J=8.9, 21.5 Hz, 1H), 3.52 (dd, J=10.5, 21.5Hz, 1H), 5.98 (s, 1H), 6.35 (d, J=6 Hz, 1H), 6.42 (d, J=6 Hz, 1H), 6.63(s, 1H), 7.82 (s, 1H);

¹³ C-NMR (D₂ O) δ 68.05 (d, J=149 Hz), 88.01, 112.20 (d, J=10.6 Hz),115.69, 131.47, 135.57, 140.63, 153.51, 156.67, 161.09.

Example 67 (2R,5R)-1- 2,5-Dihydro-5-(phosphonomethoxy)-2-furanyl!uracilammonium salt ##STR89##

To a solution of the product of Example 57 (500 mg, 1.65 mmol) in DMF (3mL) at 0° C. was added freshly distilled bromotrimethylsilane (3 mL).After being stirred at 0° C. for 2 hr, the volatiles were removed invacuo and the residue was dissolved in concentrated NH₄ OH (5 mL) andre-evaporated in vacuo. The residual oil was purified by C₁₈reverse-phase column under 8 psi of pressure using water as eluent togive the product (300 mg, 56%) as a white amorphous solid: m.p. 140° C.(dec.); UV_(max) (H₂ O) 262 nm (ε 9097);

¹ H-NMR (D₂ O) δ 3.55 (dd, J=9.3, 12.6 Hz, 1H), 3.71 (dd, J=9.3, 12.6Hz, 1H), 5.79 (d, J=8.1 Hz, 1H), 5.86 (s, 1H), 6.15 (d, J=6.0 Hz, 1H),6.36 (d, J=6.0 Hz, 1H), 6.76 (s, 1H), 7.57 (d, J=8.1 Hz, 1H).

¹³ C-NMR (D₂ O) 72.38 (d, J=155 Hz), 94.92, 109.62, 116.25 (d, J=12 Hz),136.22, 139.74, 149.46, 158.97, 173.49.

Example 68 (2R,5R)-1-2,3,4,5-Tetrahydro-5-(phosphonomethoxy)-2-furanyl!uracil ammonium salt##STR90##

A solution of the product of Example 67 (100 mg, 0.3 mmol) in EtOH-water(4:1) (10 mL) was hydrogenated in the presence of 10% Pd/C (100 mg) at 5psi for 2 hr. The mixture was filtered through Celite, and the filtratewas concentrated in vacuo. The residue was purified by C₁₈ reverse-phasecolumn under 8 psi of pressure using water as eluent to give the product(65 mg, 63%) as a white solid: m.p. 134° C.; UV_(max) (H₂ O) 261 nm (ε9115);

¹ H-NMR (D₂ O) δ 2.1-2.4 (m, 4H), 3.56 (dd, J=9.6, 13.0 Hz, 1H), 3.76(dd, J=9.9, 13.0 Hz, 1H), 5.26 (d, J=3.0 Hz, 1H), 5.89 (d, J=8.3 Hz,1H), 6.34 (t, J=6.6 Hz, 1H), 7.88 (d, J=8.3 Hz, 1H);

¹³ C-NMR (D₂ O) δ 35.30, 38.08, 70.72 (d, J=159 Hz), 93.56, 109.78,113.43 (d,J=12 Hz) , 149.72, 159.15, 173.50.

Anal. Calcd. for C₉ H₁₆ N₃ O₇ P.2H₂ O: C, 31.32; H, 5.84; N, 12.17.Found: C, 31.59; H, 5.60; N, 11.96.

Example 69 (2R,5R)-1-2,5-Dihydro-5-(phosphonomethoxy)-2-furanyl!cytosine ammonium salt##STR91##

To a solution of the product of Example 57 (550 mg, 17.3 mmol) inpyridine (16 mL) was added 2-chlorophenyl dichlorophosphate (0.8 mL, 4.8mmol) and 1,2,4-triazole (760 mg, 11 mmol). After being stirred at 23°C. for 15 hr, concentrated ammonium hydroxide (3 mL) was added to thereaction mixture and the resulting yellow solution was kept at 23° C.for 2 hr. All volatiles were removed in vacuo and the residual mixturewas passed through a silica gel pad using CH₂ Cl₂ /10% MeOH as eluent.The filtrate was evaporated in vacuo and the residual oil was dissolvedin DMF (4 mL). To this solution, freshly distilled bromotrimethylsilane(4 mL) was added at 0° C. After being stirred at 0° C. for 2 hr, allvolatiles were removed in vacuo and the residual oil was purified by C₁₈reverse-phase column under 8 psi of pressure using water/10% MeOH aseluent to give the product (130 mg, 24%) as a white powder. UV_(max) (H₂O) 270 nm (ε 6268);

¹ H-NMR (D₂ O) δ 3.72 (dd, J=9.3, 12.3 Hz, 1H), 3.84 (dd, J=9.3, 13.2Hz, 1H), 5.89 (s, 1H), 6.17 (d, J=7.8 Hz, 1H), 6.22 (d, J=6 Hz, 1H),6.41 (d, J=6 Hz, 1H), 6.83 (s, 1H), 7.80 (d, J=7.8 Hz, 1H).

Anal. Calcd. for C₉ H₁₅ N₄ O₆ P.H₂ O: C, 33.24; H, 4.96; N, 12.92.Found: C, 32.95; H, 4.61; N, 13.20.

Example 70 (2R,5R)-1-2,3,4,5-tetrahydro-5-(phosphonomethoxy)-2-furanyl!cytosine ammonium salt##STR92##

A solution of the product from Example 69 (100 mg, 0.33 mmol) inwater-EtOH (1:4) (10 mL) was hydrogenated in the presence of Pd/C (100mg) at 5 psi for 2 hr. The mixture was filtered through Celite, and thefiltrate was concentrated in vacuo. The residual oil was purified on aC₁₈ reverse phase column under 8 psi of pressure using water as eluentto give the product (20 mg, 20%) as a white powder: UV_(max) (H₂ O) 272nm (ε 7200);

¹ H-NMR (D₂ O) δ 2.1-2.5 (m, 4H), 3.54 (dd, J=9.9, 12.9 Hz, 1H), 3.77(dd, J=9.0, 12.9 Hz, 1H), 5.29 (d, J=3.0 Hz, 1H), 6.09 (d, J=7.5 Hz,1H), 6.35 (t, J=6.6 Hz, 1H), 7.91 (d, J=7.5 Hz, 1H);

¹³ C-NMR (D₂ O) δ 35.98, 37.97, 71.05, (d, J=158 Hz), 94.36, 103.77,113.70 (d, J=13 Hz), 143.68, 149.52, 164.87, 173.11.

Example 71 (2R,4S,5R)-1-Tetrahydro-4-phenylselenyl)-5-(dimethoxyphosphinyl)methoxy-2-furanyl!-5-ethyluracil##STR93## A. 2'-Deoxy-5-ethyluridine-5'-carboxylic acid

The platinum-catalyzed oxidation of 2'-deoxy-5-ethyluridine wasaccomplished by following the literature procedure (Moss, G. P.; Reese,C. B.; Schofield, K.; Shapiro, R.; Todd, A. R., J. Chem. Soc. (1963)1149) to give the noted product in 75% yield as an amorphous powder:

¹ H-NMR (D₂ O) δ 1.07 (t, J=7.5 Hz, 3H), 2.2-2.5 (m, 4H), 4.68 (s, 1H),6.43 (t, J=7.5 Hz, 1H), 7.92 (s, 1H).

Anal. Calcd. for C₁₁ H₁₄ N₂ O₆ : C, 48.90; H, 5.23; N, 10.37. Found: C,48.70; H, 5.22; N, 10.02.

B. A solution of the product of part A (7.9 g, 29 mmol) anddimethylformamide dineopentylacetal (32 mL) in DMF (100 mL) was heatedat 110° C. for 6 hr. After cooling, the reaction mixture was evaporatedin vacuo. The resulting residual oil was chromatographed on silica gelusing CH₂ Cl₂ /5% MeOH as eluent to give the intermediate product (5.3g, 86%) as a white amorphous powder.

¹ H-NMR (CDCl₃) δ 1.08 (t, J=7.5 Hz, 3H), 2.28 (q, J=7.5 Hz, 2H),2.5-2.65 (m, 1H), 3.1-3.2 (m, 1H), 5.11 (dd, J=2.7, 5.4 Hz, 1H), 6.45(dd, J=2.7, 4.8 Hz, 1H), 6.68 (dd, J=4.5, 10.8 Hz, 1H), 6.96 (s, 1H),8.39 (br s, 1H).

Anal. Calcd. for C₁₀ H₁₂ N₂ O₃ : C, 57.69; H, 5.81; N, 13.46. Found: C,57.67; H, 5.79; N, 13.33.

C. To a solution of the glycal product of Step B (2.0 g, 9.6 mmol) anddimethyl(hydroxymethyl)phosphonate (9.4 g, 70 mmol) in CH₂ Cl₂ (20 mL)at 23° C. was added N-(phenylseleno)phthalimide (6.1 g, 20 mmol) and themixture was heated at 85° C. for 2 hr. After cooling, the reaction wasdiluted with CH₂ Cl₂ (300 mL) washed with water and brine, dried overMgSO₄, and concentrated in vacuo. The residual oil was chromatographedon silica gel using CH₂ Cl₂ /5% MeOH as eluent to give the final product(3.5 g, 72%) as a hard oil:

¹ H-NMR (CDCl₃) 1.08 (t, J=7.4 Hz, 3H), 2.3-2.5 (m, 3H), 3.75 (d, J=10.8Hz, 6H), 3.7-3.9 (m, 3H), 5.13 (s, 1H), 6.53 (t, J=7.1 Hz, 1H), 7.2-7.6(m, 5H).

Anal. Calcd. for C₁₉ H₂₅ O₇ PSe.H₂ O: C, 43.73; H, 5.18; N, 5.37. Found:C, 43.29; H, 5.30; N, 5.02.

Example 72 (2R,5R)-1-2-5-Dihydro-5-(dimethylphosphinyl)methoxy-2-furanyl!-5-ethyluracil##STR94##

A solution of the product of Example 71 (3.5 g, 6.9 mmol), NaHCO₃ (2.3g, 27 mmol) and 30% H₂ O₂ (2.9 mL) in 1,4-dioxane-water (2:1, 50 mL) wasstirred at 23° C. for 2 hr. All volatiles were removed in vacuo and theresidue was extracted with CH₂ Cl₂ (100 mL). The CH₂ Cl₂ was evaporatedto dryness, and the residual oil was chromatographed on silica gel usingCH₂ Cl₂ /5% MeOH as eluent to give the product (1.8 g, 75%) as acolorless oil;

¹ H-NMR (CDCl₃) δ 0.87 (t, J=7.5 Hz, 3H), 2.05 (q, J=7.5 Hz, 2H), 3.52(d, J=10.8 Hz, 3H), 3.56 (d, J=10.8 Hz, 3H), 3.87 (dd, J=9.3, 12.3 Hz,1H), 3.95 (dd, J=9.3, 12.3 Hz, 1H), 5.58 (s, 1H), 6.0 (d, J=4.5 Hz, 1H),6.14 (d, J=4.5 Hz, 1H), 6.67 (s, 1H), 6.98 (s, 1H).

Anal. Calcd. for C₁₃ H₁₉ N₁₉ OP: C, 45.10; H, 5.54; N, 8.10. Found: C,45.14; H, 5.50; N, 7.96.

Example 73 (2R,5R)-1-2,5-Dihydro-5-(phosphonomethoxy)-2-furanyl!-5-ethyluracil ammonium salt##STR95##

To a solution of the product of Example 72 (300 mg, 0.87 mmol) in DMF (8mL) at 0° C. was added freshly distilled bromotrimethylsilane (3 mL).After being stirred at 0° C. for 2 hr, the volatiles were removed invacuo to dryness. The residue was dissolved in concentrated NH₄ OH (3mL) and then evaporated in vacuo to dryness. The residue was purified byC₁₈ reverse phase column under 8 psi of pressure using water as eluentto give the product (146 mg, 50%) as a white powder: UV_(max) (H₂ O) 266nm (ε 8710);

¹ H-NMR (D₂ O) δ 1.02 (t, J=7.4 Hz, 3H), 2.24 (q, J=7.4 Hz, 2H), 3.69(dd, J=9.3, 12.8 Hz, 1H), 5.89 (s, 1H), 6.19 (d, J=7.2 Hz, 1H), 6.38 (d,J=7.2 Hz, 1H), 6.83 (s, 1H) 7.31 (s, 1H);

¹³ C-NMR (D₂ O) δ 18.78, 26.19, 71.52 (d, J=157 Hz), 94.82, 116.09 (d,J=11 Hz), 124.42, 136.48, 139.53, 143.98, 158.93, 173.24.

Anal. Calcd. for C₁₁ H₁₈ N₃ O₇ P.H₂ O: C, 37.04; H, 5.71; N, 11.90.Found: C, 37.27, H, 5.49, N, 11.57.

Example 74 (2R, 5R)-1-2,5-Dihydro-5-(phosphonomethoxy)-2-furanyl-5-ethylcytosine ammonium salt##STR96##

The product was prepared in 50% yield in a manner analogous to thatdescribed in Example 69 except the product of Example 72 was used as thestarting material. The product was obtained as a white amorphous powderwith the following spectral characteristics: UV_(max) (H₂ O) 276 nm (ε7425);

¹ H-NMR (D₂ O) δ 1.04 (t, J=7.5 Hz, 3H), 2.26 (q, J=7.5 Hz, 2H), 3.55(dd, J=8.3, 12.9 Hz, 1H), 3.62 (dd, J=8.4, 12.9 Hz, 1H), 5.96 (s, 1H),6.14 (d, J=6.1 Hz, 1H), 6.35 (d, J=6.1 Hz, 1H), 6.78 (s, 1H) 7.31 (s,1H);

¹³ C-NMR (D₂ O) δ 18.17, 26.47, 72.55 (d, J=155 Hz), 95.83, 116.15 (d,J=12 Hz), 117.71, 137.03, 139.07, 145.11, 164.62, 172.69.

Anal. Calcd. for C₁₁ H₁₉ N₄ O₆ P.H₂ O: C, 35.48; H, 6.16: N, 16.42.Found: C, 35.79; H, 6.36; N, 16.58.

Example 75 (2R,5R)-1-2,5-Dihydro-5-(phosphonomethoxy)-2-furanyl!-5-iodocytosine ##STR97##

The product was prepared in 25% yield in a manner analogous to thatdescribed in Example 69 except that the product of Example 61 was usedas the starting material. The product was obtained as a white amorphouspowder having the following spectral characteristics:

UV_(max) (H₂ O) 286 nm (ε 8350); NMR (D₂ O) δ 3.65 (dd, J=9.3, 11.1 Hz,1H), 3.81 (dd, J=8.9, 11.1 Hz, 1H), 5.87 (s, 1H), 6.18 (d, J=5.9 Hz,1H), 6.38 (d, J=5.9 Hz, 1H), 6.76 (s, 1H), 7.82 (s, 1H), 8.29 (br s,1H).

Anal. Calcd. for C₉ H₁₄ N₄ O₆ PI.2H₂ O: C, 23.09; H, 3.85; N, 11.96.Found: C, 22.85; H, 3.99; N, 11.69.

Example 76 (2R,5R)-1-2,5-Dihydro-5-(dimethoxyphosphinyl)methoxy-2-furanyl!-5-vinyl uracil##STR98##

To a solution of the product of Example 61 (260 mg, 0.59 mmol) inN-methylpyrrolidinone (2 mL) at 23° C. was added tri-(2-furyl)phosphine(5.4 mg) and tris-(dibenzylideneacetone)dipalladium (5.4 mg). Afterbeing stirred for 15 min, vinyltributyltin (200 mg) was added and themixture was stirred at 23° C. for 30 hr. All volatiles were removed invacuo and the residual oil was chromatographed on silica gel using CH₂Cl₂ /5% MeOH as eluent to give the product (120 mg, 60%) as a colorlessoil:

¹ H-NMR (CDCl₃) δ 3.49 (d, J=6.9 Hz, 3H), 3.54 (d, J=6.9 Hz, 3H), 3.83(dd, J=8.7, 13.2 Hz, 1H), 3.93 (dd, J=8.9, 13.2 Hz, 1H), 4.95 (dd,J=1.5, 11 Hz, 1H), 5.68 (s, 1H), 5.75 (dd, J=1.5, 15.1 Hz, 1H), 6.12 (d,J=6.0 Hz, 1H), 6.16 (d, J=6.0 Hz, 1H), 6.19 (dd, J=11, 15.1 Hz, 1H),6.70 (s, 1H), 7.24 (s, 1H).

Anal. Calcd. for C₁₃ H₁₇ O₇ P.H₂ O: C, 44.20; H, 5.14; N, 7.94. Found:C, 43.91; H, 5.01: N, 7.68.

Example 77 (2R,5R)-1-2,5-Dihydro-5-(phosphonomethoxy)-2-furanyl!-5-vinyluracil ammonium salt##STR99##

To a solution of the product of Example 76 (100 mg, 0.32 mmol) in DMF (4mL) at 0° C. was added freshly distilled bromotrimethylsilane (2 mL).After being stirred at 23° C. for 2 hr, all volatiles were removed invacuo. The residue was dissolved in concentrated NH₄ OH (5 mL) and thenevaporated to dryness. The residual solid was purified by C₁₈ reversephase column chromatography under 8 psi of pressure using water aseluent to give the product (45 mg, 42%) as a white solid: m.p. 132° C.(dec.); UV_(max) (H₂ O) 284 nm (ε 7016);

¹ H-NMR (D₂ O) δ 3.64 (dd, J=9.5, 13.2 Hz, 1H), 6.19 (d, J=6.0 Hz, 1H),6.37 (d, 1H), 5.88 (s, 1H), 6.19 (d, J=6.0 Hz, 1H), 6.37 (d, J=6.0 Hz,1H), 6.39 (dd, J=11.4, 15.2 Hz, 1H), 6.85 (s, 1H), 7.59 (s, 1H).

Anal. Calcd. for C₁₁ H₁₆ N₃ O₇ P.H₂ O: C, 37.61; H, 5.12: N, 11.96.Found: C, 37.35; H, 4.95; N, 11.69.

EXAMPLE 78 9-2,3-Dideoxy-2,3-dihydro-4-β-phosphonomethoxy-β-D-erythrofuranosyl!adeninedisodium salt

The following is a preferred method for the large scale preparation ofthe corresponding disodium salt of the compound of Example 50:##STR100## A.2S-(2-a,3-b,5-a)!-5-(6-Amino-9H-purin-9-yl)tetrahydro-3-hydroxy-2-furancarboxylicacid

To a 12 liter reaction flask was added water (6 liters) and potassiumhydroxide (240 g of 85% (by assay) potassium hydroxide, 3.6 mole, 3equiv). The solution reached an internal temperature of 35° C., and2'-desoxyadenosine (300 g, 1.2 moles, Cruachem Ltd., Glasgow, Scotland,UK) was added in one portion. The 2-desoxy-adenosine dissolved in about15 min. The reaction mixture was cooled to 10°-15° C. and potassiumpermanganate (750 g, 4.7 mole, 4 equivs.) was added portionwise, over2-2.5 hr. The solution became a dark brown suspension.

After the addition was complete, the reaction was stirred for 1 hr, thenchecked by TLC (ethyl acetate:methanol:acetic acid (20:4:4), R_(f)(product) 0.3) which showed no starting material remained. Excesspermanganate was quenched by the dropwise addition to the suspension of30% hydrogen peroxide.

The reaction mixture was then filtered through a bed of Celite, and thefiltrate concentrated to about 1.5 liters in volume. This solution wasthen cooled to 10° C., and the pH slowly lowered stepwise from 13.8 to8.0 by the dropwise addition of concentrated hydrochloric acid. Themixture was filtered, the filtrate was recooled and the pH was loweredslowly from 8.0 to 4.2 as before. The product precipitated, and wascollected by filtration and washed with water, then dried in vacuoovernight. After the above procedure was repeated six times,approximately 500 g of the product were obtained which after isolationand drying was about a 22% yield.

B. (R)-9-(2,3-Dihydro-2-furanyl)-N-(dimethylamino)methyl!-9H-purin-6-amine

A suspension of the product of Part A (250 g, 0.94 mole) in drydimethylformamide (1 liter) was heated to 120° C. To the suspension wasadded dimethylformamide dineopentylacetal (920 mL, 764 g, 3.3 mole, 3.5equiv.) in a steady stream over 1 hr. The reaction was maintained at atemperature of 120° C. Heating at 120° C. was continued for 9 hr, thenthe reaction mixture was allowed to cool to 20°-25° C. Analysis by TLC(methylene chloride:methanol (90:10), R_(f) (product) 0.6) indicatedthat the reaction was complete.

The reaction mixture was filtered, removing approximately 60 grams of aninsoluble solid by-product. The filtrate was concentrated under highvacuum to a brown oil, which separated into 2 phases. The lower phasewas drawn off and stored at 0°-5° C.

A second identical run of the above procedure was performed, and thecrude products were combined. The product was partially crystallized,and was collected by filtration and washed with diethyl ether.Approximately 170 grams of product were obtained. The filtrate anddiethyl ether washings were combined and reconcentrated, and the residuechromatographed in several runs using methylene chloride:methanol (97:3)as eluent at a flow rate of approximately 100 mL/min (20 psi).Product-containing fractions were combined and concentrated in vacuo.The residue was triturated with diethyl ether, and the product combinedwith the product isolated above. Approximately 313 g of the desiredproduct (68% yield) were isolated.

C. (R)-9-(2,3-Dihydro-2-furanyl)-9H-purin-6-amine

To a suspension of the product of Step B (164 g, 0.65 mole) in methanol(400 mL) was added, in a steady stream over approximately 30 min, 30%ammonium hydroxide (400 mL). The reaction mixture became endothermic,with the internal temperature dropping to 16° C. A clear light orangecolored solution was obtained after approximately 50% of the ammoniumhydroxide had been added. The reaction mixture was stirred for 16 hr,becoming a white suspension. Analysis by TLC (methylenechloride:methanol (90:10), R_(f) (product) 0.5) indicated the reactionwas complete. The reaction mixture was cooled to 0°-5° C., and theproduct was collected by filtration, washed with water (100 mL) thentwice suspended in toluene and concentrated to dryness.

A second run on 103 g of the product of Step B was performed. Theproducts of both runs were combined, weighing 196 g for a 90% yield.

D. (R)-N- 9-(2,3-Dihydro-2-furanyl)-9H-purin-6-yl!-2,2-dimethylpropanamide

To a suspension of the product of Step C (196 g, 0.97 mole),4-dimethylaminopyridine (5.9 g, 0.048 mole) in dry pyridine (970 mL) at26° C. was added dropwise over 1 hr trimethylacetylchloride (145 mL,142.1 g, 1.18 mole, 1.2 equiv.). A slight 3° C. exotherm was noted. Thereaction mixture was then heated to 55° C. for 4 hr becoming a paleyellow-orange solution. Analysis by TLC (methylene chloride:methanol(90:10), R_(f) (product) 0.75) showed the reaction was complete. Thereaction solution was cooled to 25° C. and methanol (40 mL) was slowlyadded. The reaction solution was then stirred for 30 min, thenconcentrated in vacuo to a thick orange syrup. The residue was dissolvedin methylene chloride (1.5 liters) and washed with 0.5N sodium bisulfate(3×500 mL), 1N sodium bisulfate (2×500 mL), then brine (1×500 mL). Allaqueous washes were combined and extracted with methylene chloride(1×500 mL). All methylene chloride extracts were combined and dried overanhydrous sodium sulfate, then filtered and concentrated in vacuo to alight orange oil. The oil was suspended in toluene (200 mL) andconcentrated in vacuo. The product solidified to a pale yellow solidweighing 262 g for a yield of 94%.

E. (Hydroxymethyl)phosphonic acid, dimethyl ester

To a suspension of paraformaldehyde (173 g, 5.76 mole, 1.3 equiv.) intetrahydrofuran (1200 mL) was added triethylamine (65 mL, 47.2 g, 0.47mole, 0.1 equiv.). The mixture was stirred and heated to 65° C., anddimethylphosphite (500 g, 4.54 mole) was added dropwise at a rate tomaintain the temperature between 65° C. and 70° C. The addition wascompleted in approximately 50 min. The reaction mixture was maintainedat 70° C. for 2 hr, then allowed to cool to 25° C., standing overnight.

The reaction mixture was filtered through Celite, then concentrated invacuo to a cloudy, colorless oil, weighing approximately 600 g. The oilwas triturated with diethyl ether (4×500 mL), and toluene (3×1 liter).The crude product then was dissolved in methylene chloride and appliedto a silica gel (3 Kg) column. The product was eluted with methylenechloride:methanol (97:3). After approximately 12 liters of eluent hadbeen collected, the desired product was detected by TLC (methylenechloride:isopropanol (90:10), R_(f) (product) 0.4-0.5, visualized withalkaline potassium permaganate spray). Product containing fractions werecombined and concentrated to a colorless oil weighing approximately 340g for a 52% yield.

F. 2S-(2-a,3-b,5-a)!- 5- 6-2,2-Dimethyl-1-oxopropyl)amino!-9H-purin-9-yl!-2,5-dihydro-3-iodo-2-furanyl!oxy!methyl!phosphonicacid, dimethyl ester

A solution of the products of Step D (48 g, 0.167 mole) and Step E (233g, 1.67 mole, 10 equiv.) in methylene chloride (500 mL) was cooled to-75° C. At least a 10-fold excess of the product of Step E to theproduct of Step D is preferred for obtaining maximum yields. To thissolution was added iodine monobromide (1M in methylene chloride, 320 mL,2 equiv.) over approx 15 min. A 7° C. exotherm (-75° C. to -67° C.) wasnoted, but subsided when approximately 50% of the iodine monobromide wasadded. The reaction mixture was brought to -25° C., over 1 hr, and heldat this temperature for 4 hr, then checked by TLC (methylenechloride:methanol (95:5), R_(f) 0.6 for the product), and stirred anadditional 2 hr at -25° C.

The reaction mixture was slowly added to a biphasic mixture of methylenechloride (1000 mL), saturated sodium bicarbonate (1000 mL), and aqueous10% sodium bisulfite (250 mL). The methylene chloride layer was washedwith a 10:3 mixture of saturated sodium bicarbonate and 10% sodiumbisulfite (2×300 mL) and brine (1×300 mL). Excess iodine monobromide isquenched by addition of further sodium bisulfite, if needed, and solidsodium bicarbonate is added, as necessary to maintain the pH above 7.The methylene chloride layer was dried over sodium sulfate, thenconcentrated in vacuo to give a yellow foam weighing 88 g.

The above procedure was repeated on 2×43 portions of the compound ofStep D. The combined crude product (approximately 250 g) was dissolvedin methylene chloride:ethanol (96:4) and chromatographed in 2 runs onsilica gel columns (3.5 Kg) under 20 psi pressure at a flow rate ofapproximately 150 mL/min. Product-containing fractions were combined andconcentrated to give a yellow foam weighing 144 g over both runs for acombined yield of 55%.

G. (2S-cis)-5-(6-Amino-9H-purin-9-yl)-2,5-dihydro-2-furanyl!oxy!-methyl!phosphonicacid, dimethyl ester

A solution of the product of Step F (70 g, 0.127 mole) in dry methanol(500 mL) was made and cooled to -10° C., then sodium methoxide (180 mLof 25 wt. % in methanol, 4.4M) was added dropwise over 45 min, keepingthe temperature below 0° C. The yellow reaction solution was stirred 16hr (overnight) then checked by TLC (methylene chloride:methanol (90:10),R_(f) (product) 0.25) which showed the reaction was partially complete.The reaction solution was slowly warmed to 20°-25° C. and monitored byTLC. After 6-7 hr, the reaction appeared complete by TLC. A polarby-product (R_(f) 0.1) was observed as the reaction proceeds. Thisproduct may be partially suppressed by running the reaction at 0° C. to5° C. followed by warming the reaction to ambient temperature.

The reaction solution was cooled to 0°-5° C., and a freshly preparedsolution of hydrogen chloride in methanol was added dropwise until thereaction solution was neutral to moist litmus paper. Over-acidificationof the reaction mixture should be avoided. The reaction solution wasthen concentrated in vacuo to an oily brown semi-solid residue.

The crude product was suspended in methylene chloride:ethanol (90:10),and applied to a silica gel (3.5 Kg) column, and eluted with thissolvent mixture under pressure (20 psi, flow rate approximately 100mL/min). After collecting approximately 20 liters of eluent the desiredproduct eluted from the column. Product-containing fractions werecombined and concentrated to an off-white solid, which then was driedazeotropically from toluene. The solid isolated weighed 27.7 g for ayield of 64%.

H. (2S-cis)-5-(6-Amino-9H-purin-9-yl)-2,5-dihydro-2-furanyl!oxy!methyl!phosphonicacid, disodium salt

To a suspension of the product of Step G (27.7 g, 0.081 mole), inmethylene chloride (170 mL), was addedN-methyl-N-trimethylsilyltrifluoroacetamide (60 mL, 64.7 g, 0.325 mole,4 equiv.) The suspension was stirred for 15 min at 25° C., showing nophysical change. The reaction mixture was then cooled to -5° C., andtrimethylsilylbromide (32 mL, 37.12 g, 0.242 mole, 3 equiv.) was addedin a steady stream over 1-2 min. A slight 2° C. exotherm was noted.After the addition was complete, cooling was removed and the reactionmixture was allowed to warm to 25° C. In approximately 10 min, a clear,pale yellow solution was obtained. The reaction solution was stirred 2hr at 25° C., then checked by NMR and TLC (Merck Reverse Phase CN⁻plates, acetonitrile: H₂ O (50:50), R_(f) (product) >0.9), which showedthe reaction to be complete.

The reaction solution was rapidly added to a stirred mixture of 30%aqueous ammonium hydroxide (250 mL) and ice (250 g). The aqueous pH was11-11.5 after completing the addition. The mixture was then extractedwith methylene chloride (6×500 mL) then aqueous 1N sodium hydroxide wasadded. The aqueous solution was then placed under high vacuum for 1 hr,after which the pH measured approximately 9. The aqueous solution wasthen frozen and lyophilized to give approximately 40 g of apinkish-white solid.

The solid was redissolved in water and the pH was checked. The pH shouldbe maintained above 7 by addition of 1N sodium hydroxide. The solutionthen was applied to a 3 liter column of HP-20 resin. The column waseluted with water at a flow rate of approximately 9-10 mL/min (gravitydriven only), collecting 50 mL fractions, which were analyzed by UVvisualization and for halide with aqueous silver nitrate. Fractionstesting positive for UV activity and negative for halide were combinedand lyophilized to give a total of approximately 27.5 g of white solid.NMR analysis showed that the isolated solid was the desired compoundcontaminated with N-methyl-N-trimethylsilyltrifluoroacetamide. The solidwas dissolved in water (approximately 150 mL), filtered through a 0.2micron filter, stirred, and then 95% ethanol (1.5 liters) was rapidlyadded. The product precipitated as a thick white solid which wasfiltered and washed with ethanol. The solid was again filtered, anddissolved in water and lyophilized to give 20.5 g of product, for ayield of 71%. Spectral data indicated that the product was the desiredproduct, m.p. 283°-287° C. (dec.) Analysis by HPLC indicated a purity of>99%.

¹ H-NMR (300 MHz, D₂ O): δ 8.0 (1H, s); 7.9 (1H, s); 6.7 (2H, s); 6.5(1H, d); 6.4 (1H, d); 6.0 (1H, s); 3.6-3.4 (2H, m).

¹³ C-NMR (D₂ O): 156.0; 153.5; 149.0; 141.1; 134.0; 129.7; 119.0;(110.0; 110.6 (d)); 86.8; (67.8; 65.6 (d)).

BIOLOGICAL ACTIVITIES

The following assays were performed in cell culture systems to determinethe concentrations of compounds that are effective in preventing severalkinds of viral infections. The results are presented in Table V.

The following are abbreviations used in the description of the assayprotocols: HSV-1 (herpes simplex virus type 1, strain Schooler), HSV-2(herpes virus type 2, strain 186), VZV (varicella zoster virus, strainELLEN), HCMV (human cytomegalovirus, strain AD 169), HIV (humanimmunodeficiency virus, strain HTLV-IIIB).

Cell Culture Assays:

HSV-1, HSV-2, HCMV, and VZV antiviral assays: Virus was adsorbed toWI-38 cell culture monolayers in 6 well culture plates (Costar,Cambridge, Mass.) for 1 hr prior to addition of maintenance mediumcontaining duplicate dilutions of the test compound. Inhibition ofplaque development was evaluated on fixed and strained monolayers after4 days incubation at 37° C. for HSV-1 and HSV-2 and after 6-7 daysincubation at 37° C. for HCMV and VZV. IC₅₀ values were determined fromthe drug concentration which conferred at least 50% plaque reductioncompared to virus controls.

HIV antiviral assay:

(A) Suspensions of CEM (Nara and Fishchinger, Nature, 332:469, 1988)cells were infected at a multiplicity of infection (e.g. virus/cell) of0.12 with HIV (strain HTLV-IIIB). After adsorption for 1-2 hr at 37° C.,infected cells were diluted in growth medium (RPMI 1640 containing theantibiotics penicillin plus streptomycin and 10% fetal calf serum) to afinal cell concentration of 1×10⁴ viable cells/culture well in thepresence of serial dilutions of the test compound, starting at 100μg/mL. Triplicate samples at each drug concentration were used. Culturesof uninfected CEM cells were similarly prepared and incubated withserial dilutions of test compound in duplicate. All assays wereperformed in 96 well disposable cell culture plates. Untreated (infectedand uninfected) cells were included as controls. All cultures wereincubated for 7 days at 37° C. in a humidified atmosphere containing 5%CO₂. Following incubation, viable cell numbers were counted in each wellusing a colorimetric assay following incubation of cells with XTT-PMSsolution (XTT tetrazolium reagent plus phenazine methosulfate PMS).

Percent reduction of viral cytopathic effect (CPE) in drug treatedcompared to untreated virus infected cells, and percent reductions ofcell viability in drug treated uninfected cells compared to untreatedcontrols were calculated and plotted versus the drug concentrationstested. From these plots, the IC₅₀ (the minimum drug concentration thatinhibits CPE by 50%) and TC₅₀ (the minimum drug concentration thatreduces cell viability by 50% in drug treated, uninfected cells) foreach drug was calculated.

(B) Suspensions of MT-2 cells (S. Harada, et al., Science, 229, 563(1985)) were infected at a multiplicity of infection of 0.03 TLID₅₀/cell with HIV (strain HTLV-III B). After adsorption for 1-2 hr at 37°C., infected cells were diluted in growth medium (RPMI 1640 containingthe antibiotics penicillin plus streptomycin and 10% fetal calf serum)to give a final cell concentration of 1×10⁴ viable cells/culture well inthe presence of serial dilutions of the test compound, starting at 100μg/mL. Triplicate samples at each drug concentration were used. Culturesof uninfected MT-2 cells were similarly prepared and incubated withserial dilutions of test compound in duplicate. All assays wereperformed in 96 well disposable cell culture plates. Untreated (infectedand uninfected) cells were included as controls. All cultures wereincubated for 7 days at 37° C. in a humidified atmosphere containing 5%CO₂. Following incubation, viable cell numbers were counted in each wellusing a colorimetric assay following incubation of cells with XTT-PMSsolution (XTT tetrazolium reagent plus phenazine methosulfate PMS).

Percent reduction of viral cytopathic effect (CPE) in drug treateduninfected cells compared to untreated controls were calculated andplotted versus the drug concentrations tested. From these plots, theIC₅₀ (the minimum drug concentration that inhibits CPE by 50%) and TC₅₀(the minimum drug concentration that reduces cell viability by 50% indrug treated uninfected cells) for each drug was calculated.2',3'-Dideoxycytidine and 3'-azido-3'-deoxythymidine were used as apositive drug control.

                  TABLE V                                                         ______________________________________                                        IN VITRO ANTIVIRAL ACTIVITY                                                               IC.sub.50 /TC.sub.50 (μg/mL)                                   Cmpd. of    HIV-1                                                             Example     MT-2 cells     CEM cells                                          ______________________________________                                        73          >100/>100      >100/>100                                          74          >100/>100      >100/>100                                          77          >100/76        >100/96                                            75          >100/>100      >100.sup.1 />100                                   62          >100/>100      39->100/>100                                       59          13-27/>100     10-24/>100                                         25          85/>100        29/>100                                            66          68/>100        18/>100                                            ddc         0.13-0.79/>10  <0.03/2.5-5.1                                      AZT         <0.03-0.15/>10 >0.03/6.4->10                                      ______________________________________                                         .sup.1 39% reduction in viral cytopathic effect at 100 μg/mL.         

What is claimed is:
 1. A compound of formula (VI) ##STR101## wherein Xis halogen, Y is S-phenyl, Se-phenyl or halogen and B is hypoxanthine,xanthine, guanine, 8-bromoguanine, 8-chloroguanine, 8-methylguanine,8-thioguanine, 3-deazaguanine, purine, 2-aminopurine, 2,6-diaminopurine,adenine, 3-deazaadenine, 8-aminoguanine, 8-hydrazinoguanine,8-hydroxyguanine, cytosine, 5-ethylcytosine, 5-methylcytosine, thymine,uracil, 5-chlorouracil, 5-bromouracil, 5-ethyluracil, 5-iodouracil,5-propyluracil or 5-vinyluracil, 2-acetamido-6-diphenylcarbamoylpurine,6-N-dimethylamino-methyladenine or 6-N-pivaloyladenine.
 2. A compound offormula (VII) ##STR102## wherein B is guanine, 8-bromoguanine,8-chloroguanine, 8-methylguanine, 8-thioguanine, 3-deazaguanine,8-aminoguanine, 8-hydrazinoguanine, 8-hydroxyguanine, cytosine,5-ethylcytosine, or 5-methylcytosine.
 3. The compound of claim 1 whereinB is 6-N-pivaloyladenine, adenine, 3-deazaadenine, guanine,8-bromoguanine, 8-chloroguanine, 8-methylguanine, 8-thioguanine,3-deazaguanine, 8-aminoguanine, 8-hydrazinoguanine, 8-hydroxyguanine,cytosine, 5-ethylcytosine, or 5-methylcytosine.
 4. The compound of claim1 wherein B is substituted at the 1-position of a pyrimidine base or the9-position of a purine base.
 5. The compound of claim 1 wherein X ishalogen and Y is Se-phenyl.